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An activity theory approach to analysing student learning of human anatomy using a 3D-printed model and a digital resource
No full textIntroduction
The availability of different tools for teaching and learning has made it challenging for educators to determine which tools are more effective and appropriate for helping students achieve learning outcomes. This is particularly evident in teaching human anatomy, where a range of modalities is used to complement cadaveric dissection. Despite the positive reception of these tools, their impact on learning outcomes remains uncertain. To address this issue, we utilise the Activity Theory Framework to analyse students’ interaction with two tools – a 3D-printed (3DP) model and a digital resource (DR) – to answer two clinical questions relating to the lower spine.
Method
This study took place in a graduate medical school in Singapore. Forty-six students voluntarily signed up for the session. They were grouped in small teams of between 4 and 6 students, and interactions were video recorded. Using a cross-over design, five groups answered a clinical scenario using a 3DP lumbar spine model, while the other five groups used the DR. The teams then swapped the 3DP with the DR and vice versa to answer a second clinical scenario of similar difficulty.
Results
There was no significant performance difference in terms of scores. Using a case study approach, we found that students engaged in more authentic discussions using the 3DP compared to the DR. Despite having access to the system early in the semester, students appeared unfamiliar with using the DR, struggling initially to navigate the software. We found the 3DP model encouraged collaborative discussion as students could physically use it as a tool for discussion by pointing and manipulating the different components in three dimensions, which could not be done with the DR as it operates on a two-dimensional screen.
Conclusion
This study used activity theory to understand the impact of two educational tools on learning. Activity theory allowed a better understanding of tools’ dynamics in learning when looking beyond score performance. We found that 3DP better encouraged collaboration among students than DR. Educators must consider the ease of use of the learning tools when designing activities so that learners will utilise the system’s affordances
A proximal Newton adaptive importance sampler
No full textAdaptive importance sampling (AIS) algorithms are a rising methodology in signal processing, statistics, and machine learning. An effective adaptation of the proposals is key for the success of AIS. Recent works have shown that gradient information about the involved target density can greatly boost performance, but its applicability is restricted to differentiable targets. In this letter, we propose a proximal Newton adaptive importance sampler for the estimation of expectations with respect to non-smooth target distributions. We implement a scaled Newton proximal gradient method to adapt the proposal distributions, enabling efficient and optimized moves even when the target distribution lacks differentiability. We show the good performance of the algorithm in two scenarios: one with convex constraints and another with non-smooth sparse priors
Modelling thermal runaway of cylindrical battery under sub-atmospheric pressure
No full textThe storage and transportation of lithium-ion batteries under reduced ambient pressure have critical safety concerns. This work develops a model to simulate and understand the thermal runaway of a cylindrical battery cell at different sub-atmospheric pressures. A lumped heat transfer model for batteries is upgraded by considering the increasing electrolyte loss observed in experiments as pressure decreases. Using the model, we examine the impacts of ambient pressure, cell heating rate, and safety-venting threshold on battery thermal failure, with a particular focus on safety venting and thermal runaway. Before safety venting, the internal cell pressure is raised initially by electrolyte vaporisation and then by gases produced from chemical reactions. As the safety valve threshold rises from 1.2 MPa to 2.2 MPa, the gas from SEI decomposition increases from 73.5 % to 82.3 % at the moment of safety venting. The incubation period between venting and thermal runaway increases as the ambient pressure decreases. In other words, lowering the ambient pressure allows more emergency response time before thermal runaway. The developed model approach and simulations improve our understanding of thermal runaway under low ambient pressures and provide novel insights for ensuring battery safety in storage and transportation
Stability of stationary states for mean field models with multichromatic interaction potentials
No full textWe consider weakly interacting diffusions on the torus, for multichromatic interaction potentials. We
consider interaction potentials that are not H-stable, leading to phase transitions in the mean field limit.
We show that the mean field dynamics can exhibit multipeak stationary states, where the number of peaks
is related to the number of nonzero Fourier modes of the interaction. We also consider the effect of a
confining potential on the structure of nonuniform steady states. We approach the problem by means of
analysis, perturbation theory and numerical simulations for the interacting particle systems and the PDEs
A systematic review evaluating imaging techniques to determine chronicity of deep vein thrombosis
No full textObjective
The objective of this systematic review is to evaluate the different imaging techniques used to assess thrombus chronicity in patients with deep venous thrombosis (DVT).
Methods
A systematic search of Medline, EMBASE, CENTRAL and Web of Science databases was performed to identify meta-analyses, systematic reviews, randomised controlled trials or observational studies investigating imaging techniques for assessing DVT chronicity.
Results
Overall, 56 studies were reviewed. Various imaging modalities have been explored to assess DVT chronicity. Ultrasound parameters such as echogenicity and vein diameter proved unreliable, though elastography showed promise by quantifying thrombus stiffness. Computed Tomography (CT) studies were limited. In contrast, Magnetic Resonance Imaging (MRI) demonstrated potential for differentiating thrombus age, and nuclear imaging with targeted radiotracers, along with techniques like photoacoustic imaging and Optical coherence tomography (OCT), offered high diagnostic accuracy.
Conclusion
This review evaluated various imaging techniques for thrombus aging. No single modality is ideal, but MRI shows the greatest potential for advancement. In select populations, it may enhance cost-effectiveness and improve outcomes for catheter-based DVT interventions
Attenuated mental symptoms in the general population: first data from the observational cross-sectional ATTENTION study in Greece
No full textBackground
It has been reported that abnormal experiences could be common in the general “healthy” population, with the vast majority of individuals never proceeding to manifest a frank mental disorder.
Aims
This study aimed to quantify subthreshold psychiatric symptoms in the general population.
Methods
The protocol included clinicodemographic data and a mental symptoms questionnaire, and additionally, the CES-D, STAI-S, RASS, and the GloDiS to assess depression, anxiety, suicidality, and functional impairment, respectively. The data were collected online and anonymously from 1504 persons (75.66% females; 23.73% males). Descriptive statistics, risk ratios, and factor analysis were utilized.
Results
Clinical depression was present in approximately 10%, any somatic disorder in 20.21% (9.90% both), and a history of any mental disorder was present in 42.75%. The healthy individuals (46.94% of the study sample) were experiencing distress (8.6%) and subthreshold mental symptoms (attenuated psychotic, schizotypal distrust, emotional lability, conformity, and interpersonal and social functioning). Attenuated psychotic symptoms are present in almost 10%, and the conversion rate to any kind of psychosis was probably 0.5% per year until the age of 40, with one-third of these persons eventually converting. Beyond the age of 40, no conversion to psychosis seems to occur. All aspects of symptoms correlated weakly but significantly with aspects of functional impairment.
Conclusions
The results of the current study are in accord with the literature and suggest that a significant number of persons in the general population experience attenuated psychiatric symptoms and mild functional impairment without ever manifesting an overt mental disorder. There is a need for further research on this matter to confirm these findings and to explore their implications both for mental and somatic health and the provision of health care
Correction: Potential public health impacts of gonorrhea vaccination programmes under declining incidences: a modeling study
No full text[This corrects the article DOI: 10.1371/journal.pmed.1004521.]
Early de novo T cell expansion following SARS-CoV-2 infection predicts favourable clinical and virological outcomes
No full textBackground
De novo T cell expansion to a novel viral infection is assumed to confer protection, but empirical evidence in humans is limited. The SARS-CoV-2 pandemic provided a unique opportunity to investigate de novo T cell-mediated protection in antigen-naïve individuals without the confounding effects of preexisting immune memory.
Methods
We leveraged a prospective household contact study to recruit new COVID-19 cases a median of 4 days post-SARS-CoV-2 exposure. We longitudinally enumerated SARS-CoV-2 antigen-specific functional T cell subsets using dual IFN-γ/IL-2 fluorescence-linked immunospot (FLISpot) assays. We then correlated T cell dynamics with detailed clinical and virological outcomes derived from longitudinal measurement of symptom burden and viral load.
Findings
Early expansion (day 0–7) of SARS-CoV-2-specific IFN-γ-secreting T cells correlated with lower peak viral load and symptom burden. Conversely, late T cell expansion (day 7–28) correlated with higher symptom burden. Neither pre-existing cross-reactive T cells nor early antibody induction correlated with virological outcomes.
Interpretation
These findings provide empiric evidence for early antigen-specific T cell expansion being protective against naturally acquired viral infection in humans.
Funding
This work is supported by the NIHR Health Protection Research Unit in Respiratory Infections, Imperial College London in partnership with the UK Health Security Agency (Grant number: NIHR200927; AL) and the Medical Research Council (Grant number: MR/X004058/1)
When the lights went out: impacts of the April 2025 Iberian blackout on the Portuguese National Health Service sovereignty - a reflection on national defence, health sovereignty, risk, and infrastructural dependency
No full textThe April 2025 blackout in the Iberian Peninsula severely disrupted The Portuguese National Health Service (NHS). It led to failures for over eight hours in power supply, digital systems, telecommunications, and inter-institutional coordination. Hospitals operated on limited generator capacity, essential medical equipment was triaged, and digital health records became inaccessible. Cold storage failures endangered temperature-sensitive medicines, while emergency communications and transport systems were severely compromised. This perspective article based on first-hand experience and grey literature proposes a first rapid analyses on the blackout as through the World Health Organization’s Health Emergency and Disaster Risk Management Framework. Advocating that health care resilience must then be acknowledged as a fundamental area of national security the article calls for regulatory improvement, decentralized energy solutions, digital redundancy, and integrated command structures linking health, civil protection, and defence sectors. It offers further insights into building anticipatory health systems capable of withstanding future complex disruptions
Evaluation of Moore and grab sampling method for Salmonella Typhi detection in environmental samples in Ghana
No full textBackground
Typhoid fever causes substantial mortality and morbidity in low and middle-income countries (LMICs) as a result of inadequate water, hygiene, and sanitation facilities. The gold standard for typhoid diagnosis is blood culture, however this method is expensive and mostly unavailable in LMICs. Environmental surveillance (ES) could offer a low cost alternative to identify circulation of Salmonella enterica serovar Typhi (S.Typhi) and help inform public health interventions including vaccination.
Methods
We implemented standardized protocols for ES at 40 validated sites in peri-urban communities in Ghana from July 2022 to August 2023. Grab samples (GS) and Moore swabs (MS) were collected monthly for the initial 6 months and subsequently monthly MS were maintained for the rest of the study period. Wastewater samples were tested for S. Typhi target genes (ttr, staG, tviB) and a biomarker of human faecal contamination (Bacteroides HF183) using multiplex quantitative PCR (qPCR). Clinical surveillance for typhoid fever was performed by blood culture of febrile cases presenting to the local hospital who lived in the study area.
Results
For the first 6 months of wastewater ES, we observed a higher prevalence of S. Typhi in MS compared to GS [100/240 (42%; 95% Confidence Interval [CI]: 34-50% vs. 24/240 (10%; 95% CI: 6-16%)]; p-value < 0.001]. Overall, the detection of S. Typhi throughout the study period based on MS was 42.1% (202/480; 95% CI: 35-50%). The prevalence of S. Typhi in blood culture surveillance was 0.21% [12/5,576; 95% CI: 0.12-0.38%]. Precipitation (1.1 (95% CI: 1.02-1.10) and number of wet days (2.0 (95%CI: 1.40-2.88) were positively associated with an increased odds of S. Typhi detection in MS and GS.
Conclusion
Generally the proportion of S.Typhi detections in wastewater samples was less than blood culture-based detections. Limited detection of confirmed typhoid fever cases at the local hospital may reflect healthcare seeking behaviours, access as well as early treatment with over-the-counter antibiotics. Further work is required to confirm these qPCR detections with amplicon sequencing methods. Strategies also needs to be developed for integration of ES into public health decision making for the prevention of typhoid fever