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Social networking site use, depressive and anxiety symptoms in adolescents: evidence from a longitudinal cohort study (SCAMP)
No full textBackground
The growing and pervasive use of social network sites (SNS) has raised concerns about their impact on adolescent mental health during this sensitive developmental phase. Existing longitudinal studies are constrained by methodological limitations and limited exploration of underlying mechanisms. We investigated the longitudinal associations between SNS use and depressive and anxiety symptoms in adolescents and whether sleep mediated these associations.
Methods
We analysed longitudinal data from 2350 adolescents from 31 schools in London, participating in the Study of Cognition, Adolescents, and Mobile Phones (SCAMP). The exposure was self-reported duration of SNS use at baseline (aged 11–12 years). Outcomes were depressive and anxiety symptoms at follow-up, analysed as symptom severity and clinically significant symptoms (aged 13–15 years). The associations between SNS use and depressive and anxiety symptoms were assessed via multi-level ordinal logistic regression (symptom severity) and logistic regression (clinically significant symptoms). The mediation effects of insufficient sleep, sleep onset latency, and sleep disturbance were assessed by mediation analysis.
Results
Compared to 0–30 min per day, more than 3 h per day of SNS use at baseline was associated with higher severity levels of depressive and anxiety symptoms (adjusted odds ratio (OR) = 1.47, 95% CI 1.12, 1.93 and OR = 1.40, 95% CI 1.06, 1.83, respectively) and clinically significant depressive and anxiety symptoms at follow-up (OR = 1.70, 95% CI 1.19, 2.42 and OR = 1.60, 95% CI 1.11, 2.31, respectively). The associations between total and weekend SNS use and depressive symptom severity were stronger in girls than boys. Other associations were similar by gender. Insufficient sleep duration (particularly on weekdays) and sleep onset latency at baseline partly mediated the associations of SNS use and depressive and anxiety symptoms (proportion of mediation ranged between 11.1% and 33.1%). The mediation effects of sleep disturbance were less marked.
Conclusions
In a large longitudinal cohort, we found that SNS use exceeding 3 h per day is associated with increased risks of depressive and anxiety symptoms in adolescents. Findings from mediation analysis suggest that addressing poor sleep hygiene in relation to SNS use might mitigate the negative impact of high SNS use. Our findings may inform the development of early secondary school curricula incorporating digital literacy and sleep hygiene education
An analysis of the performance of various equations of state for ammonia and hydrogen as pure fluids
No full textHydrogen and ammonia are both promising alternative fuels. The development of new technologies utilising these fuels will require accurate thermodynamic modelling. In this work, several EOS (equations of state) were evaluated for hydrogen and am monia density modelling. In total 13 different EOS were considered, including the ideal gas law, 4 cubic EOS, 4 Helmholtz EOS and 4 SAFT (statistical associating fluid theory) EOS. These equations were assessed against experimental density measurements from literature in the superheated, subcooled and supercritical regions. Temperatures ranged between 14 K to 1,500 K and 223 K to 406 K and pressures between 1 bar to 18,710 bar and 0.3 bar to 9,500 bar for hydrogen and ammonia respectively. For hydrogen, the ideal gas law presents an error below 5 %, compared to experimental data, if pressures are kept below 100 bar and temperatures above 100 K. Therefore, it is suitable for most engineering applications involving hydrogen, if Joule-Thomson effects are considered negligible. For ammonia, the ideal gas law is only suitable for pressures below 10 bar and at the gaseous state, while the cubic EOS considered are only applicable in the superheated region. The EOS by Haar and Gallagher (1978) had the widest ranges of temperature and pressure with den sity errors below 5 %, but its unphysical Joule-Thomson inversion curve suggests it cannot be used for calculating other thermodynamic properties such as heat capacity or speed of sound. The equation by Gao et al. (2023) is the most suitable EOS for ammonia modelling considered in this work, as it can be applied to a wide range of temperatures and pressures and demonstrates a reasonable inversion curve. The SAFT EOS by Grandjean et al. (2014) and Mejbri and Bellagi (2006) are applicable over all phase regions, and result in a realistic inversion curve, but their pressure and temperature ranges are more limited than Gao et al. (2023)
Electronic coherence formation in the Radiationless S₂ decay of pyrazine: Quantum Ehrenfest simulations focused on the branching space of the conical intersection
No full textWe investigate the formation of electronic coherences in pyrazine following excitation to the S2 1B2u (ππ*) state (D2h) and relaxation via a conical intersection (CI) to the S1 1B3u (nπ*) state. In our Quantum Ehrenfest (Qu-Eh) simulations, Gaussian wavepackets (GWPs) are started in the positive and negative directions of all the selected normal modes. The GWPs moving along the derivative coupling vector cross the CI and generate coherences from time zero. The effect nevertheless cancels in the total wavefunction because the wavepackets have opposite geometric phases. Thus, our results support the theoretical conjecture which states that coherences should not be observable if the intersecting states have different Abelian point group symmetries at the Franck-Condon (FC) point. However, if initial conditions start with a small admixture of the second coupled state, in this case the S1 1B3u (nπ*) state, rather than a pure S2 state, one generates an initial gradient along either the positive or negative direction of the derivative coupling vector, thus biasing the motion of the wavepacket so that the coherence becomes non-zero
Temporal comorbidity patterns in Alzheimer’s disease and vascular dementia: a population-based observational study inn UK Biobank
No full textIntroduction: In Alzheimer’s Disease and Vascular Dementia, comorbidities shape disease trajectories and care needs, yet their timing across the lifespan remains poorly understood.
Methods: We analysed comorbidities using in-patient hospital ICD-10 codes in 10,730 UK Biobank participants with Alzheimer’s Disease or Vascular Dementia, spanning 20 years before to 10 years after diagnosis. Logistic regression and Bayesian Network Analysis identified time- and subtype-specific risk patterns, validated against controls.
Results: Distinct comorbidities emerged decades before diagnosis. In Alzheimer’s Disease, depressive episodes, osteoporosis, and type 1 diabetes appeared up to 20 years pre-diagnosis, while Vascular Dementia was characterised by early cerebral infarctions, type 1 diabetes, intestinal disorders, and rheumatoid arthritis, absent in controls.
Discussion: Although restricted to severe populations captured in in-patient data, excluding primary care, these findings reveal time-dependent prodromal patterns in Alzheimer’s Disease and Vascular Dementia, highlighting opportunities for targeted screening, prevention, and early intervention
Optimal choice of proxy for cloud condensation nuclei reduces uncertainty in aerosol-cloud-climate forcing
No full textAerosol-cloud interactions (ACI) remain the largest uncertainty in anthropogenic climate forcings. Observation-based estimates of instantaneous radiative forcing from ACI (RFaci; the Twomey effect) rely on the choice of aerosol quantities as proxies for cloud condensation nuclei (CCN) concentrations, which differ in their ability to represent cloud-base CCN and data accuracy. Using diverse observations and aerosol-climate models, we evaluate the utility of different proxies with two independent approaches. Both approaches reveal that surface CCN exhibits the smallest bias in predicting RFaci (+5%), followed by aerosol index, surface sulfate and column CCN with similar biases of +25%, while aerosol optical depth and column sulfate show the largest biases (−60% and +92%). Constraining RFaci with the optimal proxy reduces uncertainty from 66 to 43%, yielding a less negative RFaci (−1.0 W m−2) than the unconstrained case (−1.2 W m−2). Our findings highlight the crucial role of proxy constraint in reconciling and improving RFaci estimates
Piezo1-mediated mechanohydraulic control of cell volume drives cardiac morphogenesis
No full textOrgan morphogenesis is driven by physical forces, yet how mechanical stimuli pattern tissue shape and guide developmental programs remains poorly understood. In zebrafish, endocardial cells (EdCs) within the heart valve-forming region undergo marked volume reduction during
early morphogenesis. Here, we uncover a hydraulics-based mechanism by which mechanical forces control EdC volume to direct cardiac development. We show that the mechanosensitive ion channel Piezo1 acts with the calcium-binding protein calmodulin (CaM) and the aquaporin Aqp8a.1 water channel to orchestrate EdC shrinkage. We find that Aqp8a.1 mediates cell volume loss by incorporating into the plasma membrane in response to mechanical stimulation, promoting heart looping and valve formation. Mechanistically, Piezo1 governs Aqp8a.1
through a dual mechanism. First, Piezo1 and CaM drive Aqp8a.1 plasma membrane incorporation, enabling rapid cell volume adjustments. Second, Piezo1 suppresses aqp8a.1 transcription via Notch1b signaling to prevent excessive shrinkage. Altogether, these findings reveal that mechanotransduction can dictate organ formation through dynamic cell volume regulation, uncovering a fundamental principle of morphogenesis
ArgLLM-App: an interactive system for argumentative reasoning with large language models
No full textArgumentative LLMs (ArgLLMs) are an existing approach leveraging Large Language Models (LLMs) and computational argumentation for decision-making, with the aim of making the resulting decisions faithfully explainable to and contestable by humans. Here we propose a web-based system implementing ArgLLM-empowered
agents for binary tasks. ArgLLM-App supports visualisation of the produced explanations and interaction with human users, allowing them to identify and contest any mistakes in the system’s reasoning. It is highly modular and enables drawing information from trusted external sources. A video demonstration of ArgLLM-App is available at https://youtu.be/vzwlGOr0sP
Understanding mechanisms of learning: a realist evaluation of the MRes research methods module
No full textPreprint versionAims/Purpose: This study conducted a realist evaluation of an MRes Research Module to identify what mechanisms enable or hinder learning, for whom, and in what contexts.
Background: Research methods training is a cornerstone of postgraduate education. It is designed to support students in independent research. However, while research methods training is vital in postgraduate education, its effectiveness varies, and there is a need to understand the causal links between teaching strategies and student outcomes.
Methodology: A qualitative, realist evaluation approach was employed in the study, analysing postgraduate student experiences through the Context-Mechanism-Outcome (CMO) framework to explain how and why specific strategies succeeded or failed.
Results: Workshops, authentic assessments and field-specific supervision were effective mechanisms for learning. However, generic materials and inconsistent support hindered progress, particularly for postgraduate students in computational or dry-lab disciplines, leading to uneven outcomes.
Contribution: This study proposes the ‘Adaptive Nexus Model for Postgraduate Training’ to resolve the inequities of ‘one-size-fits-all’ module designs. This model provides context-sensitive recommendations for developing more equitable and effective postgraduate training, such as creating field-specific learning pathways to support diverse student cohorts better and ensuring that all master's students are equipped for success
Grantham Institute - climate change and the environment | what we do
No full textThe Grantham Institute brings together world-leading research, education and innovation to drive effective action on the climate and nature crises. In this brochure, you’ll discover more about our work, the people behind it and the impact we’re making
Tissue penetration of anti-tumour necrosis factor therapy in perianal fistulising Crohn's disease: a proof-of-concept study
No full textBackground
Perianal fistulising Crohn’s disease (pfCD) remains a therapeutic challenge, with a limited sustained response to biological therapy. Although higher serum anti-tumour necrosis factor (TNF) levels are associated with improved fistula healing, tissue pharmacokinetics in pfCD are poorly understood. This proof-of-concept study aimed to establish the feasibility of quantifying anti-TNF concentrations within fistula tissue and evaluate their relationship with serum levels and treatment outcomes.
Methods
Paired blood and fistula tract biopsies were obtained from 14 patients (infliximab, seven; adalimumab, seven) with active pfCD on established anti-TNF therapy (>14 weeks post-induction). The serum was processed by centrifugation within 8 h and stored at −80°C. Fistula tract biopsies were snap-frozen, homogenised, and extracted using an ELISA buffer proportional to tissue weight. Anti-TNF levels in the serum and tissue supernatants were quantified using standard and high-sensitivity ELISA assays, respectively.
Results
All patients had detectable anti-TNF concentrations in both serum and fistula tissues. Tissue and serum levels showed a moderate positive correlation (r = 0.45, P = 0.09), with a stronger and statistically significant association in the infliximab subgroup (r = 0.81, P = 0.01). Higher fistula-to-serum ratios, reflecting enhanced tissue penetration, tended towards improved clinical and radiological outcomes and lower perianal disease activity index scores, although the difference was not statistically significant.
Conclusion
Anti-TNF levels in perianal fistula tissue are measurable and correlated with serum concentrations, supporting a mechanistic link between systemic exposure and local drug penetration. These findings highlight the feasibility of tissue-level pharmacokinetic assessments and warrant validation in larger prospective cohorts