16 research outputs found

    Manganese containing copper aluminate catalysts:Genesis of structures and active sites for hydrogenation of aldehydes

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    Copper aluminate spinel (CuO.CuAl2O4) is the favoured Cr-free substitute for the copper chromite catalyst (CuO.CuCr2O4) in the industrial hydrogenation of aldehydes. New insights in the catalytic mechanism were obtained by systematically studying the structure and activity of these catalysts including effects of manganese as a catalyst component. The hydrogenation of butyraldehyde to butanol was studied as a model reaction and the active structure was characterised using X-ray diffraction, temperature programmed reduction, N2O chemisorption, EXAFS and XANES, including in-situ investigations. The active catalyst is a reduced spinel lattice that is stabilised by protons, with copper metal nanoparticles grown upon its surface. Incorporation of Mn into the spinel lattice has a profound effect on the spinel structure. Mn stabilises the spinel towards reduction of CuII to Cu0 by occupation of tetrahedral sites with Mn cations, but also causes decreased catalytic activity. Structural data, combined with the effect on catalysis, indicate a predominantly interface-based reaction mechanism, involving both the spinel and copper nanoparticle surface in protonation and reduction of the aldehyde. The electron reservoir of the metallic copper particles is regenerated by the dissociative adsorption and oxidation of H2 on the metal surface. The generated protons are stored in the spinel phase, acting as proton reservoir. Cu(I) species located within the spinel and identified by XANES are probably not involved in the catalytic cycle

    Molybdenum Oxide Supported on Ti3AlC2 is an Active Reverse Water−Gas Shift Catalyst

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    MAX phases are layered ternary carbides or nitrides that are attractive for catalysis applications due to their unusual set of properties. They show high thermal stability like ceramics, but they are also tough, ductile, and good conductors of heat and electricity like metals. Here, we study the potential of the Ti(3)AlC(2 )MAX phase as a support for molybdenum oxide for the reverse water-gas shift (RWGS) reaction, comparing this new catalyst to more traditional materials. The catalyst showed higher turnover frequency values than MoO3/TiO2 and MoO3/Al2O3 catalysts, due to the outstanding electronic properties of the Ti3AlC2 support. We observed a charge transfer effect from the electronically rich Ti3AlC2 MAX phase to the catalyst surface, which in turn enhances the reducibility of MoO3 species during reaction. The redox properties of the MoO3/Ti3AlC2 catalyst improve its RWGS intrinsic activity compared to TiO2- and Al2O3-based catalysts

    Modelling the impact of wastewater flows and management practices on antimicrobial resistance in dairy farms

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    Dairy slurry is a major source of environmental contamination with antimicrobial resistant genes and bacteria. We developed mathematical models and conducted on-farm research to explore the impact of wastewater flows and management practices on antimicrobial resistance (AMR) in slurry. Temporal fluctuations in cephalosporin-resistant Escherichia coli were observed and attributed to farm activities, specifically the disposal of spent copper and zinc footbath into the slurry system. Our model revealed that resistance should be more frequently observed with relevant determinants encoded chromosomally rather than on plasmids, which was supported by reanalysis of sequenced genomes from the farm. Additionally, lower resistance levels were predicted in conditions with lower growth and higher death rates. The use of muck heap effluent for washing dirty channels did not explain the fluctuations in cephalosporin resistance. These results highlight farm-specific opportunities to reduce AMR pollution, beyond antibiotic use reduction, including careful disposal or recycling of waste antimicrobial metals

    Modelling the impact of wastewater flows and management practices on antimicrobial resistance in dairy farms

    Get PDF
    Dairy slurry is a major source of environmental contamination with antimicrobial resistant genes and bacteria. We developed mathematical models and conducted on-farm research to explore the impact of wastewater flows and management practices on antimicrobial resistance (AMR) in slurry. Temporal fluctuations in cephalosporin-resistant Escherichia coli were observed and attributed to farm activities, specifically the disposal of spent copper and zinc footbath into the slurry system. Our model revealed that resistance should be more frequently observed with relevant determinants encoded chromosomally rather than on plasmids, which was supported by reanalysis of sequenced genomes from the farm. Additionally, lower resistance levels were predicted in conditions with lower growth and higher death rates. The use of muck heap effluent for washing dirty channels did not explain the fluctuations in cephalosporin resistance. These results highlight farm-specific opportunities to reduce AMR pollution, beyond antibiotic use reduction, including careful disposal or recycling of waste antimicrobial metals

    Modelling the impact of wastewater flows and management practices on antimicrobial resistance in dairy farms

    Get PDF
    Dairy slurry is a major source of environmental contamination with antimicrobial resistant genes and bacteria. We developed mathematical models and conducted on-farm research to explore the impact of wastewater flows and management practices on antimicrobial resistance (AMR) in slurry. Temporal fluctuations in cephalosporin-resistant Escherichia coli were observed and attributed to farm activities, specifically the disposal of spent copper and zinc footbath into the slurry system. Our model revealed that resistance should be more frequently observed with relevant determinants encoded chromosomally rather than on plasmids, which was supported by reanalysis of sequenced genomes from the farm. Additionally, lower resistance levels were predicted in conditions with lower growth and higher death rates. The use of muck heap effluent for washing dirty channels did not explain the fluctuations in cephalosporin resistance. These results highlight farm-specific opportunities to reduce AMR pollution, beyond antibiotic use reduction, including careful disposal or recycling of waste antimicrobial metals. Antimicrobial resistance (AMR) is one of the most important global public health problems. It is estimated that 1.27 million deaths were attributed to AMR bacteria globally in 2019 1 , and, unless suitable countermeasures are taken, that number is predicted to rise to 10 million by 2050 2. AMR is driven by antibiotic use; the majority (73%) of antibiotic (Ab) sales are for use for food-producing livestock 3. The use of Abs in agriculture can result in drug-resistant strains infecting human populations through the food chain 4,5 , or may lead to the transfer of antibiotic resistance genes (ARGs) from livestock-associated bacteria to human-acquired infections 6-8. The importance of mitigating the risks of AMR in the agricultural sector has been recognised by many countries, including the UK, the European Union and the UN 2,9 , with reductions and restrictions being imposed on Ab use in agriculture, particularly on human critical antibiotics. However, despite a 55% reduction in Ab use in the UK agriculture sector since 2014 10 , use remains high, representing 36% of the total UK Ab use 11 , with consequent risk of spread of ARGs and AMR. In addition to antibiotics, other antimicrobials such as metals (copper and zinc) and other chemicals (e.g., formalin, disinfectants) are widely used across farms globally, particularly in footbaths to prevent lameness in livestock-a prevalent concern in dairy and sheep farming 12. Metals and other antimicrobial agents (such as formalin and glutaraldehyde) are known to have a co-selective effect on antibiotic resistance, allowing for th

    Genetic mechanisms of critical illness in COVID-19.

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    Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 ×  10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice

    Uptake of pharmaceuticals by sorbent-amended struvite fertilisers recovered from human urine and their bioaccumulation in tomato fruit

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    Struvite precipitation is a well-documented method for recovering up to 98% of phosphorus from urine, which is one of the main nutrients in fertilizers besides nitrogen and potassium. Shortcomings of this process, however, are the low nitrogen recovery ratio and the possible uptake of pharmaceuticals from urine. In this work, the NH4 + adsorbent materials biochar and zeolite are coupled with struvite precipitation to increase the N-recovery of struvite from 5.7% to 9.8%. Since nitrogen is one of the main nutrients in fertilisers, this increase is of significance for its potential commercial use. In addition, urine is spiked with pharmaceuticals to measure the consequential uptake in struvite-based fertilisers and crops afterwards. Five fertilisers are prepared by nutrient recovery from spiked urine using: (1) struvite crystallisation, (2) struvite crystallisation combined with N adsorption on zeolite, (3) struvite crystallisation combined with N adsorption on biochar, (4) N adsorption on zeolite without struvite crystallisation, and (5) N adsorption on biochar without struvite crystallisation. The fertiliser with the highest purity product and the lowest uptake of pharmaceuticals was struvite combined with zeolite. Next, the contaminated struvite-sorbent fertilisers are tested in a crop trial in which the bioaccumulation of pharmaceuticals in edible plant tissue (tomatoes) is measured. This bioaccumulation in tomato fruit biomass from each of the spiked fertilisers in the crop trial was found to be lower than 0.0003% in all cases, far below the acceptable daily intake (ADI) levels (750 kg of dry tomatoes should be consumed per day to reach the ADI limit). Consequently, the subsequent risk to human health from tomato fruit grown using urine derived struvite-sorbent fertilisers is found to be insignificant

    Psychosocial outcomes and health service use after notifying women participating in population breast screening when they have dense breasts: a BreastScreen Queensland randomised controlled trial

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    Background: Robust evidence regarding the benefits and harms of notifying Australian women when routine breast screening identifies that they have dense breasts is needed for informing future mammography population screening practice and policy. Objectives: To assess the psychosocial and health services use effects of notifying women participating in population-based breast cancer screening that they have dense breasts; to examine whether the mode of communicating this information about its implications (print, online formats) influences these effects. Methods and analysis: The study population comprises women aged 40 years or older who attend BreastScreen Queensland Sunshine Coast services for mammographic screening and are found to have dense breasts (BI-RADS density C or D). The randomised controlled trial includes three arms (952 women each): standard BreastScreen care (no notification of breast density; control arm); notification of dense breasts in screening results letter and print health literacy-sensitive information (intervention arm 1) or a link or QR code to online video-based health literacy-sensitive information (intervention arm 2). Baseline demographic data will be obtained from BreastScreen Queensland. Outcomes data will be collected in questionnaires at baseline and eight weeks, twelve months, and 27 months after breast screening. Primary outcomes will be psychological outcomes and health service use; secondary outcomes will be supplemental screening outcomes, cancer worry, perceived breast cancer risk, knowledge about breast density, future mammographic screening intentions, and acceptability of notification about dense breasts. Ethics approval: Gold Coast Hospital and Health Service Ethics Committee (HREC/2023/QGC/89770); Sunshine Coast Hospital and Health Service Research Governance and Development (SSA/2023/QSC/89770). Dissemination of findings: Findings will be reported in peer- reviewed journals and at national and international conferences. They will also be reported to BreastScreen Queensland, BreastScreen Australia, Cancer Australia, and other bodies involved in cancer care and screening, including patient and support organisations. Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12623000001695p (prospective: 9 January 2023)
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