Gustavus Adolphus College Collections
Not a member yet
92910 research outputs found
Sort by
Influence of cross-shear and contact stress on the wear of UHMWPE on boost-diffusion-treated additively manufactured Ti-6Al-4V
No full textThe more widespread adoption of additive manufacturing (AM) in the biomedical industry has enabled the production of patient-specific implants. When used in joint replacements (or as a bearing material), it is essential to understand the wear behaviour of additively manufactured implants when subjected to loading and motion that simulate their intended use. The aim of this study was to investigate the influence of cross-shear and contact stress on the wear behaviour of ultra-high molecular weight polyethene (UHMWPE) against boost-diffusion-treated (BD-treated) AM Ti-6Al-4V under varying conditions. Multidirectional pin-on-plate wear testing was conducted across cross-shear ratios from 0 to 0.3 and contact stresses ranging from 0.56 to 14 MPa. Surface characterisation techniques were used before and after wear testing to gain insights into the wear mechanisms. The wear of UHMWPE against BD-treated Ti-6Al-4V was compared to that of CoCr and untreated wrought Ti-6Al-4V. Results revealed that against BD-treated Ti-6Al-4V, UHMWPE wear was initially high due to the high surface roughness; however, continued wear testing led to polishing of the BD-treated Ti-6Al-4V, a reduction in the dynamic friction coefficient, and a decrease in wear rate. The high initial surface finish of the BD-treated Ti-6Al-4V resulted from the oxidation heat treatments. However, following wear testing surface degradation was absent, highlighting the potential benefit of the surface treatment in AM patient-specific implants
ESPNet: Edge-Aware Feature Shrinkage Pyramid for Polyp Segmentation
No full textDespite numerous techniques developed for polyp segmentation, the issue of generalizability to new centers and populations persists. To address these issues, we compile a multicenter train set consisting of 4,000 polyp frames and propose a novel approach toward generalizing to different data centers, difficult polyp morphologies (e.g., flat or small), and inflammatory conditions such as inflammatory bowel disease (IBD). In this regard, we propose a transformer-based polyp segmentation model to leverage global contextual information, and enhancement of local feature interactions through a novel feature decoding and fusion method, and polyp edge features. This combines the vision transformers’ strong contextual understanding with enhanced locality modeling through graph-based relational understanding and multiscale feature aggregation. We compare our model with eight recent state-of-the-art methods under five widely used metrics on the following benchmark datasets: Kvasir-Sessile, SUN-SEG-Easy (Seen), ETIS-LaribPolypDB, CVC-ColonDB, PolypGen-C6, and our in-house IBD dataset. Extensive experiments show that our model outperforms state-of-the-art methods on out-of-distribution datasets with mIoU improvements of 2.84% on ETIS-LaribPolypDB, 1.26% on CVC-ColonDB, 1.90% on PolypGen-C6, and 3.52% on the in-house IBD polyp dataset compared to the most accurate recent method. The code is available at https://github.com/Raneem-MT/ESPNet
Housing First for Middle Aged and Older Women:The Emerging Case
No full textThis paper explores the use of Housing First services for women experiencing homelessness, focusing on those aged 35 and over, who have multiple and complex needs. The paper draws on an evidence review and the results of a five-year evaluation of a Housing First for Women pilot project (2015-20) and three-year longitudinal study of two further Housing First services for Women in the UK (2021-24), which centred on the lived experience of women using these services. Four main arguments are advanced. The first is that the original Housing First model from the US and the initial deployments of the Housing First approach in Europe and the UK used a model designed in a context in which the nature and extent of middle aged and older women’s homelessness was poorly understood. High fidelity Housing First services were less likely to be fully effective because the original model did not properly account for the level of trauma associated with domestic abuse and violence against women in middle age and later life. The second argument is that there is, on current and emergent evidence, a clear case for developing Housing First that is designed, managed and run by women for women which includes safeguarding as one of its key operating principles. The third argument is that Housing First for Women, with its comprehensive co-productive support and intensive case management, may offer important advantages over Sanctuary Schemes and other services that are designed to counteract middle aged and older women’s homelessness that is associated with abuse, violence and multiple and complex needs. The paper concludes by arguing that in order to fully meet the needs of middle aged and older women experiencing long term and repeated homelessness with multiple and complex needs, an integrated and preventative strategy, including preventative approaches like Domestic Abuse Housing Alliance (DAHA) Accreditation and Housing First for Women must be developed. If Housing First for Women is to be effective, it must be situated within a wider integrated strategy to counteract women’s homelessness to reach its full potential
Targeting angiogenesis and white matter repair for enhanced functional recovery after acute ischemic stroke: a focus on the roles of glial cells
No full textNeural network connections require adequate blood flow to deliver sufficient oxygen and glucose. Acute ischemic stroke (AIS) significantly impairs neural function due to insufficient blood flow, leading to diffuse microvascular dysfunction and compromised white matter integrity, both indicators of poor prognosis. Post-stroke neural recovery hinges on promoting neovascularization around the infarct and restoring white matter integrity. Therefore, strategies to enhance angiogenesis and white matter repair are crucial for post-stroke neuro-rehabilitation. Emerging research highlights the pivotal roles of activated microglia, astrocytes, and oligodendrocyte precursor cells in facilitating neurogenesis, angiogenesis, and neural functional recovery following cerebral ischemia. In this review, we explore the mechanisms by which these neuroglial cells contribute to angiogenesis and white matter repair after AIS. We also propose potential therapeutic strategies that target the intricate interactions at the glial cell-endothelial cell interface. A deeper understanding of oligovascular signaling in ischemic conditions could unveil novel therapeutic targets for improving outcomes after AIS
Reasonable Doubt in the Face of Bias:Fair Flagging with Dirichlet-Based Models
No full textEnsuring safety in machine learning requires not only robustness to adversarial or distributional uncertainty but also protection against systematic bias. Models that produce unfair or group dependent predictions pose critical risks when deployed in socially sensitive domains such as credit, justice, or healthcare. This work introduces EviFair, a fairness-aware safety monitor that flags predictions exhibiting excessive dependence on protected attributes. EviFair combines evidential uncertainty modelling with sensitivity analysis to detect biased decision paths, flagging predictions where fairness cannot be guaranteed. We also show that EviFair’s bias scores can effectively guide post-processing fairness methods. Results on standard fairness benchmark datasets show that EviFair achieves substantial reductions in group disparities with minimal impact on predictive performance, demonstrating its promise as a practical, inference-time mechanism for bias-sensitive, safety-aware model oversight
A critical comparison of polypropylene and polyurethane sling materials after implantation in a suburethral sheep model
No full textAlthough polypropylene (PP) materials have been implanted for decades for urethral support in the pelvic floor, appropriate large animal models and advanced materials analysis techniques have not previously been used to investigate the clinical problems they can cause - inflammation, pain and erosion through tissues An ovine model duplicating the surgical procedure for suburethral sling surgery was developed. Here we present the results after 3 months implantation using immunohistochemistry and advanced materials characterisation of two materials PP and Polyurethane (PU). Both materials were well integrated into the tissue. The M1/M2 ratio in PP-implanted tissue was statistically significantly elevated (4.29) compared to PU (0.63) and control tissue (0.34). The higher ratio indicates a more inflammatory response to PP than PU. Surface roughness (assessed using atomic force microscopy) increased in both materials, Rq from 5.73-10.2nm in PP and from 1.03-2.96nm in PU; whilst Ra went from 4.75-7.85nm in PP and from 0.81-2.36nm in PU. Notably, surface stiffness increased by 0.05GPa in PP and decreased by 0.2GPa in PU. PP underwent both surface and bulk material degradation, PU did not. Detailed testing of implantable materials in an appropriate animal model should be conducted before materials are introduced into clinical practice. It is salutary that this has never been reported before. The use of material characterisation techniques allowed us to identify problems in the performance of PP, notably surface degradation, changes in bulk properties and stiffening, which can activate macrophages. In contrast, PU appears a more suitable alternative material for use in treating patients with SUI
Relating digital platform synergy and SME agility: The roles of organizational inertia and modularity
No full textOrganizational agility is vital for the survival of small and medium-sized enterprises (SMEs) in turbulent environments. While several studies have examined the role of digital platforms in shaping organizational agility, the impact of digital platform synergy on organizational agility in the context of SMEs remains underresearched. To address this gap, we examine the impact of SMEs’ digital platform synergy on their organizational agility and identify the mechanisms underlying this relationship. Using a sample of 421 Chinese manufacturing SMEs, the analysis demonstrates that digital platform synergy inhibits organizational agility. Furthermore, organizational inertia mediates this relationship, while organizational modularity negatively moderates the positive effect of digital platform synergy on organizational inertia, thereby reducing the mediating effect of organizational inertia. The study advances the growing literature on the factors influencing the agility of SMEs in digital contexts by illuminating the nuanced roles of digital platform synergy, organizational inertia, and modularity
Outdoor lighting and active travel: a high-resolution analysis using satellite imagery and Strava data in Glasgow
No full textIntroduction:
The benefits of active travel are well-established. While previous research has explored how built environment factors (such as population density, accessibility, land use, and infrastructure) influence active travel, micro-scale features like outdoor lighting have received less attention. This study examines associations between outdoor lighting levels and active travel in Glasgow, accounting for broader contextual factors and distinguishing between daylight and dark conditions.
Methods:
We used Strava data, satellite-derived outdoor lighting imagery, and other spatial datasets aggregated to small-area zones in Glasgow. Bayesian spatial models (Besag–York–Mollié) were fitted to estimate associations between contextual variables and distances travelled on foot, by bike, and by both modes combined, separately for daylight and dark hours.
Results:
Outdoor lighting levels derived from night-time satellite imagery were positively associated with walking, cycling, and overall active-travel distances during both light conditions (daylight and dark). These associations were stronger during dark hours, particularly for cycling. Several contextual relationships also varied by light condition: industrial density was positively associated with cycling only during daylight, while quietness and gradient showed stronger associations during daylight. Population and income deprivation were negatively associated across all modes under both light conditions.
Conclusions:
Our findings underscore the potential relevance of lighting in shaping active travel patterns after dark, particularly for cycling. They also highlight the need for future research that considers light conditions and time of day in environmental studies of mobility, as well as across broader contexts, specific locations, and diverse population groups – to better inform equitable and effective active travel policy
The feasibility of implementing a hospital deprescribing behaviour change intervention and undertaking trial processes: a mixed methods evaluation
No full textBACKGROUND: CompreHensive geriAtRician-led MEdication Review (CHARMER) is a behaviour change intervention designed to address the determinants of geriatricians and pharmacists deprescribing in hospital. CHARMER comprises a deprescribing action plan, deprescribing briefings, videos of successful deprescribing consultations, deprescribing case studies workshop and a deprescribing performance dashboard. This study aimed to evaluate the feasibility of undertaking a CHARMER definitive trial and inform primary outcome measure selection (90-day hospital readmission or patient quality of life (QoL)).
METHODS: A two-arm purposive allocation feasibility study was undertaken in four hospitals (three intervention, one control). Intervention fidelity and acceptability, outcome data completeness and quality were evaluated alongside acceptability of data collection methods. The process evaluation explored these via interviews with staff and patients. Data were used to inform primary outcome measure selection.
RESULTS: Eighteen geriatricians and pharmacists received the CHARMER intervention and 318 patients admitted to study wards were enrolled. 90-day hospital readmission data were available for 290 (91.2 %) patients. Sixty-six (20.8 %) were approached for consent to complete QoL measures; 25 (37.9 %) consented and 13 (52 %) completed at baseline and 90-day follow up. All intervention components were implemented with acceptable fidelity; hospitals were unfamiliar with implementing action plans and unclear who should be involved with implementing the dashboard, leading to delays.
CONCLUSIONS: The CHARMER intervention is feasible to implement and given the low patient consent rate, 90-day readmission rate is the most appropriate primary outcome measure. Minor refinements to guidance will facilitate hospitals to undertake activities for implementation that are unfamiliar.
CLINICAL TRIAL REGISTRATION: The study was registered on ISRCTN (ISRCTN11899506)