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The effect of molecular shape and chemical structure on the photo-physical properties of liquid crystals
Get PDFFluorescence in liquid crystals (LCs) is valuable for applications such as optoelectronic devices, photovoltaics and light emitting diodes. The molecular shape and chemical structure of LCs greatly influence their fluorescent properties, although these relationships are not well understood. We here provide a systematic comparative study of a selection of cyanobiphenyl-based LCs with both calamitic and dimeric molecular shapes. The influence of both these molecular shapes and of lateral fluorination on the observed fluorescence is determined. Our results show that cyanobiphenyl-based calamitic nematic LCs exhibit a constant increase in the excimer-to-monomer emission ratio as the temperature is reduced from the isotropic phase. For a cyanobiphenyl-based dimeric LC with an average bent (or banana) molecular shape, that exbibits both nematic and twist-bend nematic phases, the excimer-to-monomer ratio is found to be constant within both the isotropic and the nematic phases. However, interestingly, a significant increase in the excimer-to-monomer ratio is observed in the lower temperature twist-bend nematic phase of this material, indicating an increased presence of anti-parallel (AP) pairing modes. When the same dimeric LC is fluorinated laterally to the cyano group, the material shows significantly less excimer emission compared to the non-fluorinated dimeric LCs due to an interruption in AP pairing. Furthermore, the results on cyanobiphenyl-based LCs are compared with results for an oxadiazole-based nematic bent-core LC that does not support the same AP pairing modes. For the oxadiazole-based LC, we observe a constant excimer-to-monomer ratio that is significantly smaller compared with that observed for the other LCs throughout the entire temperature-range of the nematic phase. Our results clearly demonstrate that the fluorescence of cyanobiphenyl-based LCs, directly linked to excimer formation, is almost exclusively a result of AP pair formation. Importantly, we also demonstrate that this pair formation, and thus the fluorescence, can be tuned both through modification of the molecular shape and chemical structure
The association of maternal education with access to maternal care and child mortality in Nigeria:A secondary data regression-based analysis
No full textResearch Digest Number 5: Housing First:EPOCH Practice evidence review
Get PDFThere is a large international evidence base on Housing First. Many of the studies that have been conducted are American or Canadian. This research digest focuses on European research and analysis of Housing First services and programmes. Housing First is the most significant change in homelessness policy and practice that has occurred in the last thirty years. The Housing First approach has proven effectiveness in ending long term and repeated homelessness among people with multiple and complex needs in many European countries and beyond Europ
The sensitivity of smoke aerosol dispersion to smoke injection height and source-strength: a multi-model AeroCom study
Get PDFThe near-source and downwind impacts of smoke aerosols depend on both emitted mass and injection height. This study examines aerosol dispersion sensitivity to these factors using four global models from the AeroCom Phase III Biomass Burning Emission and Injection Height (BBEIH) experiment. Each model performed four simulations: BASE, using burned-area-based BB emissions GFED4.1s with default injection heights; BBIH, using monthly MISR plume injection heights; BBEM, using fire- radiative-power-based BB emission FEERv1.0; and NOBB, excluding BB emissions. The focus is the April 2008 Siberian wildfire event. Aerosol optical depth (AOD) varies across models. In BASE, all models show a steeper AOD decline from the source to downwind regions than satellite data, indicating inadequate long-range transport or excessive aerosol removal in all models. Moreover, near-source, most models overestimate aerosol extinction below 2 km, suggesting injection heights are too low. In BBIH, MISR plume injection heights slightly improve vertical aerosol distribution, but the magnitude is too small. In BBEM, AOD increases significantly near the source due to enhanced BB emissions; however, the downwind AOD remains largely underestimated in both BBIH and BBEM. Notably, CALIOP lidar reveals aerosol layers above 6 km from source to downwind regions – features absent in all model simulations, although a high bias in the gridded CALIOP data makes the evaluation inconclusive. These results suggest that monthly MISR plume injection heights and enhanced BB emissions alone are insufficient to resolve the model–observation discrepancies. Injecting smoke at higher altitudes in Siberia and reducing aerosol wet removal warrant further investigation
Game Theoretical Analysis of Geosystem Service Management:A Systematic Literature Review
No full textExploring the values and preferences of children and adolescents with obesity and their parents/caregivers concerning diet or physical activity interventions for weight management: mega-ethnography of qualitative syntheses
Get PDFIntroduction
Obesity and overweight are a global health problem affecting over 2.6 billion people worldwide. Diet and physical activity, including structured exercise, are critical components in the management of obesity. This review of reviews explores the values and preferences of children, adolescents, and their parents/caregivers that influence engagement and adherence to dietary and physical activity interventions for obesity management.
Methods
Eleven electronic databases were searched (from January 2010 to June 2024) to identify reviews incorporating qualitative research on values and preferences, attitudes or experiences of children or adolescents with obesity, or their caregivers, in relation to diet or physical activity interventions. Supplementary grey literature searching, citation searching and reference lists screening of included reviews were also undertaken. The methodological quality of included reviews was appraised using the Swedish Agency for Health Technology Assessment (SBU) tool. Data synthesis was performed using a mega-ethnography approach.
Results
Fourteen reviews were included with majority of studies conducted in high-income countries. Six key factors were identified that affect children and adolescents or their caregivers when initiating and continuing with physical activity and/or dietary management interventions. These included perceptions concerning the value of interventions; competing priorities; the role of social support; the physical environment; the nature and content of the intervention; and costs.
Conclusion
Multiple factors influence engagement with diet and physical activity programmes among children and adolescents with obesity and their caregivers, highlighting the need for emotional and psychological support, whole-family involvement, and personalised, trust-based guidance from health professionals. However, these findings are context-dependent with evidence primarily from high-income countries, which may limit their wider generalisability
Hydrodynamic interactions between pairs of sedimenting semi-flexible Brownian fibers
Get PDFThe sedimentation of semiflexible fibers is a central process in the production of a range of important materials such as paper and fiber-reinforced composites. Predicting the dynamics of such fibers when both Brownian motion and hydrodynamic interactions are relevant, which would be a powerful tool to support the design of these materials, is nonetheless numerically challenging. Here, we utilize a computational framework that incorporates fiber elasticity, thermal fluctuations, and hydrodynamic interactions represented as Rotne–Prager–Yamakawa kernels and perform a parametric study of the simplest system in which hydrodynamic interactions are relevant, that is, pairs of fibers starting from one of two initial configurations. We also provide analytical predictions for the initial velocity and rotation of rigid fibers in the Oseen approximation. We systematically studied the systems in which bending, thermal fluctuations, and hydrodynamic interactions are included for the sedimenting semi-flexible fibers. Our goal was to determine when one of thermal fluctuations or hydrodynamics dominates over the other, or when both must be considered together, to inform the understanding and design of such systems. The short- and long-time dynamics of the fibers are thoroughly characterized, with good agreement with the analytical calculations for the initial behavior, and the observed trends are interpreted in terms of the underlying physical mechanisms. We finish with a discussion of the use of Rotne–Prager–Yamakawa kernels over alternative frameworks such as bead models and suggest potential directions for future work
Reimagining general practice for the NHS 10-year plan: organisational culture as the social determinant of team health
Get PDFGeneral Practice in the UK faces acute pressure from rising demand, workforce shortages, and policy changes. Traditional NHS reforms, focused on financial incentives and activity targets, often overlook the human-centred complexity of primary care. This commentary presents a five-year cultural transformation at Birley Health Centre in northern England, centred on the ‘social determinants of team health’.
Drawing on organisational psychology, leadership theory, and staff experience, we outline practical strategies to build psychological safety, communication, autonomy, and inclusive leadership. Key changes included redefining non-clinical roles, improving
recruitment, fostering everyday trust, and embedding leadership based on empowerment and humility. These shifts led to lasting gains in staff morale, patient satisfaction, and care quality.
We argue that, in this organisational setting, a deliberately nurtured culture of psychological safety and relational trust became a core driver of systemic improvement, particularly vital in the post-pandemic context of recovery and workforce fatigue. Birley’s experience offers a replicable model for GP practices and policymakers seeking to revitalise primary care. As the NHS implements its 10-Year Plan, we advocate for prioritising leadership development, healthy team dynamics, and patient engagement as essential to sustainable reform
Medico-legal considerations in post-mortem imaging data: governance, ethics, and evidential use
Get PDFPost-mortem imaging, in particular CT (PMCT), is increasingly used for death investigation in England and Wales, yet unlike “live” clinical imaging, this data falls outside traditional health-record legislation, creating uncertainty around data ownership, access rights, and disclosure obligations. This review examines the current data governance landscape surrounding post-mortem imaging data, identifying critical gaps requiring national guidance. We explore fundamental questions of data control between coroners and commercial service providers, noting how the absence of standardized frameworks has resulted in substantial regional variation in practice. Key challenges include inconsistent approaches to data storage, whether on clinical or dedicated PACS systems, varying data-retention periods, and disparate policies for third-party access by researchers, legal teams, and bereaved families. The evolving role of radiologists as expert witnesses in coronial and criminal proceedings presents additional complexities, particularly regarding who is best placed to explain imaging findings in court. We propose recommendations including national standards for data governance, standardized contractual frameworks clarifying data-controller relationships, protocols for secure storage and access controls, and defined competencies for radiologists presenting evidence in legal settings. Establishing robust governance foundations for post-mortem imaging data is essential to ensure this technology serves the public interest effectively, while maintaining legal defensibility and ethical integrity
Policing and drug market-related violence: competitive, internal and enforcement-related violence in UK County Lines
Get PDFBackground
The link between drugs and violence has been widely studied across a range of academic disciplines, including criminology, sociology, psychology, and social policy. However, much of this scholarship has focused specifically on the United States, and the specific form of competitive violence between rival groups.
Objectives
This paper adds to the literature by focusing on County Lines drug markets in the United Kingdom (UK), which have been linked to increases in violence and the exploitation of young people and vulnerable adults for selling, storing or transporting illicit drugs. We utilise this case, as well as recent literature on harm reduction policing, to expand frameworks for thinking about drug market-related violence.
Methods
The analysis is based on the first national study of the policing of County Lines, which consisted of interviews with senior officers across 44 of the 45 territorial police forces in the UK, as well as additional interviews and observations in three case study areas with front-line officers, partner agencies and people with lived experiences (n=117).
Results
Our findings illustrate how the exploitation of young people and vulnerable adults could be conceptualised as an internal form of violence in County Lines in the UK. Furthermore, we highlight the need to acknowledge enforcement-related violence associated with the policing of drug markets.
Conclusions
Based on our empirical findings, we argue for a conceptual broadening of current understandings of drug market-related violence, as well as further developing harm reduction policing thinking and responses to effectively counteract all forms of violence associated with drug markets and their control
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