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Pressure and not spatial average temporal average intensity governs mechanosensitive responses of osteoblast-like cells exposed to low intensity pulsed ultrasound
Get PDFLow-intensity pulsed ultrasound (LIPUS) is approved to promote healing in non-union bone fractures in the UK (NICE) and USA (FDA). Despite extensive in vitro, pre-clinical, and clinical data indicating efficacy, patient outcomes remain inconsistent. A deeper understanding of the mechanisms by which ultrasound vibrations influence cellular behaviour is critical to optimising LIPUS for bone repair and to enable greater patient benefit. The literature offers a broad experimental base, but collective insights are hindered by two key issues: inadequate reporting of ultrasound exposure conditions, often overlooking reflections and standing waves, and reliance on spatial average temporal average intensity (ISATA) as the sole metric of ultrasound dose. While ISATA informs safety thresholds (TI, MI), it fails to describe the specific acoustic stimuli cells experience, masking variations in pressure, pulse repetition, and duty cycle.
To identify the ultrasound parameters that are most important for eliciting mechano-sensing responses in osteoblast-like cells, we systematically evaluated a 1 MHz pulsed field in a controlled cell culture environment. Immunofluorescence analysis of actin and vinculin were used to assess cytoskeletal changes in response to fully described LIPUS exposures. We identified a pulse repetition frequency (PRF) upper limit of 1 kHz, beyond which LIPUS lost efficacy in enhancing mechano-sensing. Optimal response occurred at 20 % duty cycle, 160 kPa, and 60 mW/cm2 ISATA, challenging the currently accepted standard and parameters used to operate existing clinical devices (1 MHz, 30 mW/cm2 ISATA). Our data demonstrate the necessity to report fully the parameters that describe the ultrasound dose experienced by cells to predict which conditions lead to an upregulation in mechano-sensing and that ISATA alone is not an adequate measure unless all other parameters are known and fixed. Finally, since PRF is determinant of achieving a cellular response, we reaffirm the already accepted understanding that pulsed exposures are critical to a cellular ability to detect and/or respond to ultrasound in a way that is useful for fracture repair
Leaching of legacy paper mill sludge induces lithification by cementation of fluvial sediment
Get PDFThis study investigates the formation of anthropogenic conglomeratic rock caused by the lithification of natural fluvial sediment due to calcium leaching from adjacent paper mill sludge (PMS) deposits. The research focuses on a site near Penicuik, Scotland, where historical paper mill activities resulted in calcium-rich waste accumulation. Field observations identified lithified sediment on the stream bed beneath the PMS heaps, with natural clasts cemented by calcium carbonate (CaCO₃). Microstructural analysis using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) confirmed that the cementing material is predominantly calcite. X-ray Diffraction (XRD) analysis further validated the mineralogical composition, revealing calcite-rich cementation. Stable isotope analysis (δ¹³C and δ¹⁸O) indicated a mixed carbon source, with approximately 40 % derived from atmospheric CO₂ and 60 % from lithogenic origins. These findings demonstrate that Ca2 + leached from PMS dissolved into pore water which migrated down into the fluvial sediment, facilitating calcite precipitation and binding sediment particles into a cohesive structure. This anthropogenic conglomerate challenges traditional classifications of sedimentary rocks and has implications for waste management, pollutant immobilization, and localized carbon sequestration. This anthropogenic lithification process parallels natural clastic sedimentary rock formation but occurs at the Earth's surface and on much shorter timescales. The results highlight the geochemical interactions between industrial waste and natural sediments, emphasizing human influence on sedimentary systems, bridging gaps between natural and anthropogenic geology
An edge-intelligent three-tier framework for real-time forest fire detection, integrating WSNs, WMSNs, and UAVs
No full textForest fires are becoming prevalent, threatening ecosystems, economies, and public safety while creating an urgent demand for rapid and reliable detection systems. Conventional approaches such as watchtowers, manual patrols, and satellite imaging suffer from limited coverage, delays, and inadequate precision. To address these challenges, we propose a three-tier, edge-centric framework that integrates wireless sensor networks (WSNs), wireless multimedia sensor networks (WMSNs), unmanned aerial vehicles (UAVs), and lightweight machine learning (ML) and deep learning (DL) models for efficient detection. In the first tier, scalar sensors provide early hazard identification; in the second, smart sensors execute a lightweight ML model for intermediate verification, achieving a 94% F1-score with a minimal feature set; and in the third, UAVs equipped with sensors, cameras, and a compact convolutional neural network (CNN) deliver final confirmation. The CNN achieves state-of-the-art results with a 100% F1 score on the FireMan-UAV-RGBT dataset and 99.5% on UAV-FFDB while remaining compact (1.6 MB) and efficient (157 ms inference on Raspberry Pi 5), enabling real-time edge deployment. Simulations show reduced end-to-end delay (813.59 ms) compared to WSN-only (865.84 ms) and WMSN (1066.18 ms) baselines, improved throughput (7.05 kbps vs 3.80 kbps and 3.06 kbps), and a 100% delivery ratio. Real-world WSN testbed experiments further validate the framework, achieving a 97% delivery ratio, 144.39 ms latency (vs. 258.37 ms in simulations), and energy consumption of 0.0559 J/s (closely matching 0.0442 J/s in simulations). These results collectively demonstrate the practicality and effectiveness of the framework for real-time forest fire monitoring and rapid emergency response
Symmetrisation and hyperbolicity of first-order conservation laws in large strain compressible viscoelasticity using the smoothed particle hydrodynamics method
Get PDFThis paper presents a new first-order hyperbolic framework with relaxation (or dissipation) terms for large strain viscoelastic solids. The framework is based on a compressible Maxwell-type viscoelastic model and integrates linear momentum conservation, geometric conservation laws, and evolution equations for internal variables. First, we propose a polyconvex strain energy function that is jointly convex with respect to the deformation measures and internal variables. Second, we introduce a generalised convex entropy function to symmetrise the hyperbolic system in terms of dual conjugate (entropy) variables. Third, we demonstrate that the system is hyperbolic (i.e., real wave speeds) under all deformation states, and that the relaxation terms correctly capture viscoelastic dissipation. Fourth, we present an upwinding Smoothed Particle Hydrodynamics (SPH) [1–3] scheme that enforces the second law of thermodynamics semi-discretely and uses the time rate of the generalised convex entropy to monitor internal dissipation and stabilise the simulation. Finally, the proposed framework is validated through numerical examples and benchmarked against the in-house Updated Reference Lagragian SPH [2,3] and vertex-centred finite volume [4–7] algorithms, demonstrating stability, accuracy, and consistent energy dissipation
‘I have to think about what’s next’: a qualitative exploration of psychological well-being and self-management with humour among domestic and international university students
No full textPsychological well-being and self-management are essential for university students, particularly for international students facing additional challenges. Humour is under-explored as a strategy in cross-cultural university settings. We explored how domestic and international students perceive and self-manage their psychological well-being, focusing on humour. Drawing on the extended Common-Sense Model, semi-structured interviews were conducted with 16 students from a UK university. Reflexive thematic analysis identified three themes: meaning of psychological well-being – a holistic approach, humour as an emotional and social function, and self-managing psychological well-being in practice. Personal development and cultural adaptation were key concerns. Students engaged in varied self-management strategies, with humour serving as a social and emotional resource, though often used unconsciously rather than intentionally. Findings highlight the need for culturally sensitive support and greater awareness of humour as a coping resource. They also suggest psychological well-being initiatives be integrated with educational strategies to enhance retention and achievement in diverse student populations
‘Alcohol problems are definitely twenty-four seven’—a qualitative interview study exploring the presenting features of alcohol-related ambulance call-outs in Scotland (IMPAACT study)
Get PDFIntroduction:
Alcohol contributes to at least 16% of ambulance call-outs in Scotland, placing a significant burden on emergency services. This study aimed to explore the circumstances behind these incidents from the perspective of practicing Scottish Ambulance Service (SAS) clinicians.
Methods:
We conducted in-depth qualitative interviews (median duration: 81 minutes) with 31 SAS staff, purposively sampled for diversity in gender (10 women, 21 men), region, and length of service (1–50 years; median 10). Interviews were transcribed and thematically analyzed using both deductive and inductive approaches.
Results:
Alcohol-related call-outs typically involved either chronic heavy drinking patterns mainly at home with co-existing mental, social, or emotional issues or acute intoxication in social settings. Clinicians reported a large volume of incidents and felt the public underestimated the proportion caused by chronic problems.
Conclusion:
Strategies, policies, and interventions aiming to reduce pressure on emergency services must consider how to provide or improve accessible care for people with chronic alcohol problems, as well as how to reduce acute intoxication to help reduce the amount alcohol related calls SAS staff attend
Mid-infrared InAs/InP quantum-dot lasers
Get PDFMid-infrared semiconductor lasers operating in the 2.0–5.0 μm spectral range play an important role for various applications, including trace-gas detection, biomedical analysis, and free-space optical communication. InP-based quantum-well (QW) and quantum-dash (Qdash) lasers are promising alternatives to conventional GaSb-based QW lasers because of their lower cost and mature fabrication infrastructure. However, they suffer from high threshold current density (Jth) and limited operation temperatures. InAs/InP quantum-dot (QD) lasers theoretically offer lower Jth owing to their three-dimensional carrier confinement. Nevertheless, achieving high-density, uniform InAs/InP QDs with sufficient gain for lasing over 2 μm remains a major challenge. Here, we report the first demonstration of mid-infrared InAs/InP QD lasers emitting beyond 2 μm. Five-stack InAs/In0.532Ga0.468As/InP QDs grown by molecular-beam epitaxy exhibit room-temperature photoluminescence at 2.04 μm. Edge-emitting lasers achieve lasing at 2.018 μm with a low Jth of 589 A cm−2 and a maximum operation temperature of 50 °C. Notably, the Jth per layer (118 A cm−2) is the lowest ever reported for room-temperature InP-based mid-infrared lasers, outperforming QW/Qdash counterparts. These results pave the way for a new class of low-cost, high-performance mid-infrared light sources using InAs/InP QDs, marking a notable step forward in the development of mid-infrared semiconductor lasers
First evidence of CP violation in beauty baryon to charmonium decays
Get PDFA study of the difference in the CP asymmetries between Λ
0
b → J/ψpπ− and
Λ
0
b → J/ψpK− decays, ∆ACP , is performed using proton-proton collision data
collected by the LHCb experiment in the years 2015–2018, corresponding
to an integrated luminosity of 6 fb−1
. This quantity is measured to be
∆ACP = (4.03 ± 1.18 ± 0.23)%, where the first uncertainty is statistical and the
second is systematic. When combined with the previous LHCb result, a value of
∆ACP = (4.31 ± 1.06 ± 0.28)% is obtained, corresponding to a significance of 3.9σ
against the CP symmetry hypothesis. Studies of triple-product asymmetries, which
provide an additional probe of CP violation, show no significant deviation from CP
symmetry
Statistical monitoring with novel temporal edge network processes
No full textConventional modelling of networks evolving in time focuses on capturing variations in the network structure. However, the network might be static from the origin or experience only deterministic, regulated changes in its structure, providing either a physical infrastructure or a specified connection arrangement for some other processes. Thus, to detect the change in network use, we need to focus on the processes happening on the network. In this work, we present the concept of monitoring random temporal edge network processes that take place on the edges of a graph with a fixed structure. Our framework is based on the generalized network autoregressive statistical models with time-dependent exogenous variables (GNARX models) and cumulative sum control charts. To demonstrate its effective detection of various types of changes, we conduct a simulation study and monitor cross-border physical electricity flows in Europe
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