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Adsorption phenomena and surface interactions between superplasticisers and ground blast furnace slag and metakaolin particles in alkali solutions: Implications for low-carbon cements
No full textThe performance of superplasticisers in alkali-activated materials (AAMs) remains poorly understood, limiting the wider adoption of low-carbon cement technologies. This study examines the behaviour of lignosulfonate- (LS), naphthalene- (NP), and polycarboxylate ether (PCE)-based superplasticisers in NaOH/Na₂SiO₃-activated systems with ground granulated blast furnace slag (GGBFS) and metakaolin (MK). The adsorption phenomena and polymer conformation were investigated by combining mini-slump tests (flow behaviour), ATR-FTIR (chemical interactions), DLS (polymer size), TEM-EDX (polymer conformation), zeta potential measurements (surface charge), and total organic carbon analysis (polymer uptake). Results show that in both GGBFS and MK systems, high alkalinity alters polymer ionisation, suppresses electrostatic interactions, reduces superplasticiser solubility, and drives polymer agglomeration. In GGBFS systems, Ca2+ enhances superplasticiser adsorption to solid particles. LS-based superplasticisers demonstrated superior alkaline resistance, slump retention, and adsorption capacity relative to NP and PCE. These findings provide new mechanistic insights to guide the design of high-performance superplasticisers tailored for low-carbon AAM systems
Global estimates of tuberculosis incidence during pregnancy and postpartum: a rapid review and modelling analysis
Get PDFBackground
Despite known maternal, perinatal, and infant health risks of tuberculosis during pregnancy, global estimates of incidence remain scarce. Existing estimates are outdated, and do not include the postpartum period, HIV co-infection, age, or specific changes in risk, limiting our understanding of the true scale of disease in this understudied population.
Methods
In this rapid review and modelling analysis, we estimated the global tuberculosis incidence in pregnant and postpartum women using a population-based modelling approach. We searched MEDLINE and EMBASE, with no date or language limits, and included studies reporting tuberculosis incidence in pregnancy or postpartum with suitable comparison groups; we also used Feb 6, 2025, interim data from the ongoing ORCHID cohort. We combined WHO age and sex-stratified tuberculosis incidence data with country-specific population and fertility data to estimate baseline tuberculosis incidence, and applied systematic review-based risk ratios to account for elevated increased risk during pregnancy and postpartum. Uncertainty in all inputs was propagated using standard error propagation formulae and summarised as mean tuberculosis incidence rates and mean incidence rate ratios (IRRs), each reported with 95% quantile-based uncertainty intervals (UIs).
Findings
We identified 37 studies published between 1996 and 2020, of which three were of sufficient quality to provide data for HIV-negative women. One additional study (ORCHID; Odayar et al, unpublished) provided data for women living with HIV. Compared with non-pregnant women without HIV, tuberculosis IRRs were 1·34 (95% CI 1·17–1·54) during pregnancy and 1·91 (1·53–2·39) during postpartum among HIV-negative women. For women living with HIV, IRRs were 5·73 (95% CI 2·64–10·94) during pregnancy and 3·58 (0·85–9·63) postpartum. We estimated 239 500 pregnant women (95% UI 216 300–262 800) and 97 600 postpartum women (90 100–105 200) developed tuberculosis disease globally in 2023, with HIV contributing to 21·3% (19·8–22·8) and 10·6% (9·9–11·3) of cases, respectively. The WHO African region had the highest incidence (110 600 [95% UI 96 700–124 500] in pregnant women and 40 900 [36 300–45 400] in postpartum women), followed by the South-East Asia region (79 900 [64 100–95 700] in pregnant women and 35 900 [30 800–41 100] in postpartum women).
Interpretation
Pregnant and postpartum women face substantial tuberculosis risk, yet remain under-represented in global estimates. Our findings underscore the need for improved surveillance and targeted interventions to reduce tuberculosis incidence in this group.
Funding
UK Medical Research Council
Long-term effects of vegetation cover on the rehabilitation of lead/zinc mine tailings
Get PDFPb/Zn sulfide ore is extracted from carbonate host rock by milling to grainsizes <120 μm and separation by flotation. This produces large volumes of near neutral pH tailings that must be carefully managed due to regulatory concern about the residual Pb and Zn concentrations (up to ∼0.3 % by wt. of each) and trace concentrations of other potentially toxic elements. To prevent dust formation, vegetation cover is established on inactive areas of the tailings management facility (TMF). This paper reports the changes in the chemical and microbiological composition of the tailings as a function of both time and depth.
Over the course of eight years, there is progressive oxidation of pyrite in the tailings, and accumulation of soil organic matter in the surface layers. The mobility of most potentially toxic elements is reduced due to sorption to ferric oxyhydroxides formed as a result of pyrite oxidation, although Cu is more mobile in surface layers probably due to formation of dissolved organic carbon complexes. The microbial community diversity in the surface layer increased with the age of the tailings and was similar to natural calcareous soil after 8 years. At this age the functional profile (functional diversity) of the community was similar to that of natural calcareous soil, despite differences remaining in taxonomic composition. Development of soil-like properties in the surface layer, such as increased soil organic matter content and a soil-like microbial community, suggest that the vegetation cover will be self-sustaining. Therefore, revegetation is a viable option for TMF closure planning
Spin-Polarized Nonferromagnetic Surfaces for Electrocatalysis: Chemo-Spintronics
Get PDFCatalysts achieve changes in the rate through modification of the free energy of adsorbed intermediates and transition states (TrS). Binding energies of intermediates and TrS are strongly correlated, and modifications in catalyst composition are often ineffective in breaking these correlations, leading to minimal change in rate. Such scaling relationships are reported throughout catalysis. The surface spin state of a magnetic metal can change adsorption energies, offering a way to overcome scaling relationships. However, experimentally, this approach appears reliant on the use of ferromagnetic materials, limiting applicability. Here, we show that tunable changes in electrocatalytic activity for the hydrogen evolution reaction (HER) can be achieved at (originally) nonmagnetic metals (Au and Pt) through the use of a multilayer electrode structure that contains a ferromagnetic alloy (CoB) beneath a thin (5-20 nm) film of Pt or Au. Analysis of the dependence of the catalytic current on the thickness of the Au or Pt capping layer and on the direction of the stray magnetic field allows us to rule out the presence of magnetohydrodynamic effects. Instead, we conclude that transfer of ferromagnetism from the ferromagnet to the Au or Pt takes place through proximity-induced magnetism (PIM) via exchange interactions and/or a spin polarized current. Density Functional Theory simulations trace changes in the breaking of the scaling relationship for the Tafel HER mechanism. Overall, our experiments show that thin-film electrodes, based on routine structures from the spintronics community, are a potentially versatile platform for achieving spin-polarized catalysis at originally nonmagnetic metals
Whose confidence? Regional leaders' perspectives on building confidence in a reconfigured probation service
Get PDFThe idea that the institutions of criminal justice should command the confidence of the public and other stakeholders is a taken for granted ‘good’, but one which has rarely been considered from the perspectives of operational leaders within those institutions. We also know little about what happens at times of crisis, when claims are made about the erosion of confidence and leaders are charged with rebuilding it. In this article, we seek to engage critically with the idea of confidence in one criminal justice institution – the Probation Service in England & Wales – at just such a time. Drawing on original empirical research with the 12 leaders of the recently unified service, this article focuses on the question of whose confidence matters and considers some of the challenges associated with confidence-building work from the perspectives of these leaders. Our research revealed that the stakeholder groups whose confidence most concerned them were sentencers and other partner agencies; government ministers; and their own staff within the unified service. We introduce the idea of ‘domains of confidence’ to highlight the importance of understanding perspectives on confidence (and efforts to strengthen or rebuild it) in a relational space in which the particular positionality of actors in the criminal justice field must be understood
Escaping the Capitalist Black Hole: dethroning Mammon and liberating water
Get PDFColonial legacies and neoliberal capitalism continue to underpin and intensify global water insecurity. Drawing on five years of research from the UK-funded Water Security and Sustainable Development Hub across Colombia, Ethiopia, India and Malaysia, this Research Note identifies consistent patterns of water dispossession linked to capital accumulation. Despite divergent local contexts, our findings point to a common dynamic: a ‘Capitalist Black Hole’ that draws water towards profit-driven activities through the actions of both global and local elites. We conceptualise this black hole not as a neutral or natural system but as one animated by ideology and agency. We use this metaphor to illuminate how entrenched systems of greed and wealth accumulation – what we term the throne of Mammon, the symbolic ‘ruler’ of this black hole – operate through Western-centric political and ideological frameworks that commodify water, prioritise growth and capital over equity and nature, and marginalise alternative knowledges. Here, ‘Mammon’ personifies the worship of capital and the moral–cultural logic that sustains the black hole’s gravitational pull. We argue that under current geopolitical and economic conditions, existing institutional structures are structurally inadequate to achieve just and sustainable water futures. Transformative responses must directly confront the deep-rooted power structures that govern global water security
"Well, I am now looking after this bloody rabbit!" Restorying care in the lives of people with learning disabilities
No full textThis paper seeks to explore how care has been theorised in ways that have served to exclude people with learning disabilities from being recognised as care-givers, and positioned them, instead, almost exclusively, as passive recipients of care. Working with people with learning disabilities, our aim is to explore, recognise and record caring relationships in their lives, paying attention to the care given as well as the care received by people so labelled. We follow Nishida (2022) to argue that we need to be always attentive to spaces of care as potential sites of (in)justice for people with learning disabilities who engage in caring relationships in messy dependency with others
Capturing zero-price effects in stated choice surveys: implications for willingness-to-pay and welfare
Get PDFStated choice surveys commonly used in public policy appraisal – such as in transport or environmental economics – often contrast a ‘free’ status quo alternative against a range of (policy) interventions which can be implemented at a cost. Limited attention has, however, been paid to the fact that the ‘free’ nature of the status quo (SQ) alternative may make the SQ alternative overly attractive due to the zero-price (ZP) effect. The ZP effect is a well-established notion in behavioural economics explaining the phenomenon that individuals tend to over-react to free alternatives. We present an experimental design setup allowing the separation of the ZP effect from the SQ effect together with the identification of non-linear sensitivities to costs. Choices made by students between different mobile broadband packages are used for illustrational purposes. Our analysis shows that the ZP effect is significant and the observed preference to remain in the SQ is largely due to the ZP effect. In practice, this may lead to biased welfare estimates for public policy packages if the ZP effect is not explicitly accounted for. Moreover, we also show that misspecification of the functional form for cost can lead to significant bias in WTP estimates and the ZP and SQ effects
Barriers and facilitators to the delivery of delirium care in intensive care units: an analysis informed by the Theoretical Domains Framework
Get PDFIntroduction
Delirium is common in patients who are critically ill and associated with increased mortality and long-term cognitive impairment. The objective of this study was to explore the barriers and facilitators to the use of existing ICU delirium identification tools and implementation of care protocols.
Methods
Semi-structured interviews were conducted with healthcare professionals working in UK NHS ICUs. Purposive sampling was utilised to recruit a diverse range of participants to account for profession; user status of delirium identification tools or care packages; size of unit; and UK location. Thematic analysis was undertaken using the Theoretical Domains Framework.
Results
Twenty-one ICU healthcare professionals were interviewed from 20 hospitals. Participants included consultants (n = 9); nurses (n = 8); advanced critical care practitioners (n = 2); and allied health professionals (n = 2). Five major barriers to effective delirium care emerged: lack of prioritisation; lack of structured ICU delirium care protocols; inability to implement interventions due to physical space constraints and/or lack of resources; loss of experienced staff; and changes in ICU nursing culture. Facilitators included the presence of clear protocols; continued staff training; increased awareness; delirium champions; post-ICU follow-up clinics; family engagement; effective communication; and the use of digital prompts as a component of mandatory electronic documentation.
Discussion
Although ICU delirium is acknowledged as being important by clinical staff, management is often hindered by systemic and cultural barriers. Healthcare professionals highlighted the need for protocol-driven care, enhanced training and awareness, and the inclusion of families in care processes. These findings will inform the design of a multicomponent care package to improve delirium care in the ICU
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