91 research outputs found

    Accessible and sustainable Cu(0)-mediated radical polymerisation for the functionalisation of surfaces

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    Polymer brushes have great potential for use in functionalising surfaces due to their chemical and mechanical robustness, and wide variety of useful properties including antibacterial and antifouling behaviour. One such grafted polymer of interest is poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC), shown to have excellent antibacterial behaviour due to the presence of quaternary ammonium chloride groups (QACs). Previous studies have shown that increasing the density of QACs increases the efficacy of these surfaces, therefore the production of thick PMETAC brushes is highly desirable. Cu(0)-mediated radical polymerisation (CuRP) offers a simple route to the production of these surfaces. A movement towards more sustainable chemistry has led to research into polymerisations in environmentally benign solvent, with focus placed on recycled and easily accessible catalysts. In this study, the growth of PMETAC brushes up to 300 nm dry thickness (∼ 425 nm water-swollen thickness) is demonstrated, thicker than any previous report we have found for this polymer brush. Furthermore, tap water is used as a cheap and readily available solvent, with a catalyst derived from copper wire. The use of copper wire, compared to the commonly used CuBr2 catalyst, leads to thicker coatings which also display a lower swelling ratio, implying an increased grafting density. The protocol can be continuously cycled over a 7-day period without changing the monomer solution or catalyst, with numerous wafers being functionalised over the time period with no significant reduction in grafted amount. In addition, the polymerisation can be carried out in ambient (non-inert) conditions with no degassing steps, again without with significant detriment to grafting

    A smart sewer asset information model to enable an ‘Internet of Things’ for operational wastewater management

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    Real-time prediction of flooding is vital for the successful future operational management of the UK sewerage network. Recent advances in smart infrastructure and the emergence of the Internet of Things (IoT), presents an opportunity within the wastewater sector to harness and report in real-time sewer condition data for operation management. This study presents the design and development of a prototype Smart Sewer Asset Information Model (SSAIM) for an existing sewerage network. The SSAIM, developed using Industry Foundation Class version 4 (IFC4) an open neutral data format for BIM, incorporates distributed smart sensors to enable real-time monitoring and reporting of sewer asset performance. Results describe an approach for sensor data analysis to facilitate the real-time prediction of flooding

    Archaeological Investigations at Four San Antonio Missions: Mission Trails Underground Conversion Project

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    This report contains the results of archaeological work performed by the Center for Archaeological Research (CAR) at The University of Texas San Antonio (UTSA) for City Public Service (CPS). The archaeological investigation and monitoring for the Mission Trails Underground Conversion Project was carried out under Texas Historical Commission (THC) Permit Number: 2020, and the work was conducted at each of the four historical San Antonio missions which make up San Antonio Missions National Historical Park. The Mission Trails Underground Conversion Project was created to enhance and upgrade electrical and utility connections by replacing aboveground connections with underground connections at each ofthe four missions. Mission San Juan (41BX5)-In October of 1998, personnel from CAR began archaeological investigations at Mission San Juan Capistrano in advance of the proposed installation of underground utility lines for the Mission Trails Underground Conversion Project. The purpose of the investigation was to test for intact, buried cultural features in advance of trenching activities involved in the relocation of utility lines and connections. CAR archaeologists developed a plan regarding the area to be impacted which included ten 1 x 1-m excavations units and a series of twelve shovel tests along the proposed path of the utility trench. Excavation units uncovered evidence of existing buildings, wall foundations and Colonial-period flooring episodes, revealing new data west of the known structures and not previously accounted for. Further excavations are warranted to determine the nature of features such as a Colonial-period wall revealed near one of the excavation units. This material discovered by the archaeological investigations resulted in the altering of the projected utility trench alignment to avoid disturbing deposits. Further archaeological investigations are recommended for the newly revealed features. Mission San Jose (41BX3)- In January of 1999, personnel from CAR began archaeological investigations at Mission San Jose y San Miguel de Aguayo in advance of the proposed installation of underground utility lines for the Mission Trails Underground Conversion Project. The purpose of the investigation was to test for intact, buried cultural features in advance of trenching activities involved in the relocation of utility lines and connections. CAR archaeologists conducted a series of shovel tests along the center-lines of the proposed utility trenches to identifY areas of possible impact to intact Spanish Colonial cultural materials. In addition to shovel testing, monitoring of the trenching was conducted in areas where the possibility of impacting cultural material was high. An early-twentieth century trash midden was encountered during monitoring of the trench where it paralleled the Service Drive in the northwest comer of the Mission compound. This material did not warrant altering the course of the trench, and no further archaeological work is recommended at this time. Mission Concepcion (41BX12)- In January of 1999, personnel from CAR began archaeological investigations at Mission Nuestra Senora de la Purisima Concepcion as part of the Mission Trails Underground Conversion Project. A construction crew, while excavating a manhole designed to provide access to underground electrical utilities, had unearthed a large number of animal bones. After concluding a large feature had been unexpectedly impacted, CAR conducted test excavations to ascertain the nature of this feature. It was determined to be a section of an acequia which had been refilled during the Colonial period with construction debris and trash, including a large number of animal bones. Test units and the original manhole excavations allowed for a profile of the acequia to be constructed. This information combined with previous archaeological work and historical research, allowed a tentative proposal on the sequence of acequia construction and re-routing for the Concepcion mission. Monitoring of other underground work conducted in the area resulted in the discovery of a location of a Colonial-period wall, southeast of the Visitors\u27 Center, which may be a portion of the original south wall of the mission. It is recommended that if any further work is required, consideration should be given to testing and/or monitoring to reduce the risk of negative impact to historic remains. Mission Espada (41BX4)- In July of 1999, personnel from CAR began archaeological investigations at Mission San Francisco de la Espada in advance of the proposed installation of underground utility lines for the Mission Trails Underground Conversion Project. From initial discussions, it was noted that the proximity of the proposed route of the underground utility trench could have an impact on the old compound walls of the mission and the path was altered to avoid any possible impact. A series of thirteen shovel tests were conducted in advance along the altered path of the proposed utility trench as it progressed from the southwest comer of the mission compound across the dry irrigation ditch or acequia to the northwest. Monitoring of the trenching activities followed with no significant deposits being exposed. No further work is recommended within the project area, but if future construction is to occur in the area between the utility trench and the Church at Mission Espada, monitoring should then be considered

    3D printed fluidics with embedded analytic functionality for automated reaction optimisation

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    Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis

    Switching the Interpenetration of Confined Asymmetric Polymer Brushes

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    The interpenetration of two polymer brushes on approaching flat surfaces has been investigated. When compacting polymer brushes with an asymmetric charge on each surface, one neutral and the other weakly charged, we find that the brush interpenetration becomes a parameter that can be controlled by the pH of the hydrating solution. The switching between high and low degrees of brush interpenetration was investigated with numerical self-consistent field theory (nSCF) and experimentally using a sample environment which combines neutron reflectometry with a surface force type apparatus. Initially, a pair of uncharged poly(ethylene oxide), PEO, brushes are examined, where one of the brushes is deuterated to distinguish it from a hydrogenous counterpart. We find in both nSCF and these experiments that there is no significant overlap between the brushes as both compact into polymer blocks with little hydration. However, when a weak polyelectrolyte poly(2-(dimethylamino)ethyl methacrylate), PDMAEMA, brush is confined against a deuterated neutral PEO brush and the pH of the hydrating solution is below the polycation’s pKa of 7.5, then the presence of charged groups on the PDMAEMA allows significant interpenetration to occur between the two polymer brushes on contact. This interpenetration remains once the polymer brushes dehydrate due to the confining pressure that is applied. Raising the pH to a value above the pKa, removes the charges from the polyelectrolyte brush resulting in little to no interpenetration between the two brushes. Therefore, by simply adjusting the pH of the hydrating solution the interpenetration state between polymer brush pairs can be switched when one brush is a weak polyelectrolyte. Since polymer brushes are widely investigated and used to reduce friction between solid surfaces, this effect may have significant implications in the design and operation of polymer brushes with controllable friction properties

    3D printed fluidics with embedded analytic functionality for automated reaction optimisation

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    Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis

    The effect of laser remelting on the surface chemistry of Ti6al4V components fabricated by selective laser melting

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    Surface remelting/skin scanning of components is generally performed during the selective laser melting (SLM) process to improve the surface quality of a part. However, the chemical effects of surface remelting are not well understood. In this study, cuboidal parts fabricated with and without laser remelting were characterised using scanning electron microscopy (SEM), surface profilometry and X-ray photoelectron spectrophotometry (XPS). The SEM images showed a low-amplitude undulating pattern was observed on both surfaces. The surface chemistries of the surface remelted/skin scanned (SK) and non-surface remelted/non-skin scanned (NSK) samples were observed to significantly differ in their elemental composition. The thickness of the surface oxide layer of the SK surface was double that of the NSK surface. Also, the contribution of the major alloying elements, including titanium and aluminium, on the surface oxide layer varied for both NSK and SK surfaces. The surface chemistry of the NSK and SK surface was significantly different to a conventionally forged (CF) Ti6Al4V surface. The rate of decrease of oxide with depth was in the order of CF > NSK > SK. Although surface remelting is useful in rendering improved surface quality, its impact on surface chemistry should be carefully considered

    Functionalisation of Ti6Al4V components fabricated using selective laser melting with a bioactive compound

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    Surface modification of an implant with a biomolecule is used to improve its biocompatibility and to reduce post-implant complications. In this study, a novel approach has been used to functionalise phosphonic acid monolayers with a drug. Ti6Al4V components fabricated using selective laser melting (SLM) were functionalised with Paracetamol (a pharmaceutically relevant biomolecule) using phosphonic acid based self-assembled monolayers (SAMs). The attachment, stability of the monolayers on the SLM fabricated surface and functionalisation of SAMs with Paracetamol were studied using X-ray photoelectron spectroscopy (XPS) and surface wettability measurements. The obtained results confirmed that SAMs were stable on the Ti6Al4V surface for over four weeks and then began to desorb from the surface. The reaction used to functionalise the phosphonic acid monolayers with Paracetamol was noted to be successful. Thus, the proposed method has the potential to immobilise drugs/proteins to SAM coated surfaces and improve their biocompatibility and reduce post-implant complications

    The avoiding late diagnosis of ovarian cancer (ALDO) project; A pilot national surveillance programme for women with pathogenic germline variants in BRCA1 and BRCA2

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    Background: Our study aimed to establish â € real-world' performance and cost-effectiveness of ovarian cancer (OC) surveillance in women with pathogenic germline BRCA1/2 variants who defer risk-reducing bilateral salpingo-oophorectomy (RRSO). Methods: Our study recruited 875 female BRCA1/2-heterozygotes at 13 UK centres and via an online media campaign, with 767 undergoing at least one 4-monthly surveillance test with the Risk of Ovarian Cancer Algorithm (ROCA) test. Surveillance performance was calculated with modelling of occult cancers detected at RRSO. The incremental cost-effectiveness ratio (ICER) was calculated using Markov population cohort simulation. Results: Our study identified 8 OCs during 1277 women screen years: 2 occult OCs at RRSO (both stage 1a), and 6 screen-detected; 3 of 6 (50%) were ≤stage 3a and 5 of 6 (83%) were completely surgically cytoreduced. Modelled sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for OC were 87.5% (95% CI, 47.3 to 99.7), 99.9% (99.9-100), 75% (34.9-96.8) and 99.9% (99.9-100), respectively. The predicted number of quality-Adjusted life years (QALY) gained by surveillance was 0.179 with an ICER cost-saving of-£102,496/QALY. Conclusion: OC surveillance for women deferring RRSO in a â € real-world' setting is feasible and demonstrates similar performance to research trials; it down-stages OC, leading to a high complete cytoreduction rate and is cost-saving in the UK National Health Service (NHS) setting. While RRSO remains recommended management, ROCA-based surveillance may be considered for female BRCA-heterozygotes who are deferring such surgery

    Earth Observation Technologies: Low-End-Market Disruptive Innovation

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    After decades of traditional space businesses, the space paradigm is changing. New approaches to more efficient missions in terms of costs, design, and manufacturing processes are fostered. For instance, placing big constellations of micro- and nano-satellites in Low Earth Orbit and Very Low Earth Orbit (LEO and VLEO) enables the space community to obtain a huge amount of data in near real-time with an unprecedented temporal resolution. Beyond technology innovations, other drivers promote innovation in the space sector like the increasing demand for Earth Observation (EO) data by the commercial sector. Perez et al. stated that the EO industry is the second market in terms of operative satellites (661 units), micro- and nano-satellites being the higher share of them (61%). Technological and market drivers encourage the emergence of new start-ups in the space environment like Skybox, OneWeb, Telesat, Planet, and OpenCosmos, among others, with novel business models that change the accessibility, affordability, ownership, and commercialization of space products and services. This chapter shows some results of the H2020 DISCOVERER (DISruptive teChnOlogies for VERy low Earth oRbit platforms) Project and focuses on understanding how micro- and nano-satellites have been disrupting the EO market in front of traditional platforms
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