159370 research outputs found
Sort by
Alternative sensing for state-of-charge estimation of latent heat thermal energy storage
Get PDFThermal energy storage (TES) is likely to play a significant role in the decarbonisation of domestic heat, allowing consumers to shift their energy consumption away from peak demand periods and reducing overall strain on the grid. Phase change materials (PCMs) are a promising option for TES, in which energy can be stored in the latent heat of the melting of the PCM; these offer greater storage densities than sensible heat TES and have the benefit of releasing stored heat at a consistent temperature (the crystallisation temperature of the PCM). One of the key difficulties for PCM-based TES is state of charge (SoC) estimation (the estimation of the proportion of energy stored in the TES unit up to its maximum capacity), particularly during idle periods while the unit is storing heat. SoC estimation is key to the implementation of TES, as it enables the effective control of the units. The use of a resonator within the PCM for SoC estimation could potentially provide a global estimate of the SoC, since the resonator passes through the full depth of the PCM in the unit. The SoC could be inferred by measuring the vibrational response of the resonator under excitation, which varies depending on the melt state of the PCM. This paper presents findings from a test rig investigating this proposal, including discussions on the features required from the resonator response for SoC inference
A Review of Computer Vision for Railways
Get PDFModern railways continue to strive for remote and automated methods to improve the visual inspection procedures for their assets. In some cases, these inspections provide new information that could not previously be collected, while in other cases they help them improve upon the quality control, safety, time and costs associated with manual inspection. As such, computer vision continues to find applications for visually inspecting the track, earthworks, tunnels, overhead line equipment and rolling stock. Considering the recent pace of computer vision related developments, this paper seeks to review the state of the art of the field for railways. First, the hardware and data requirements are discussed, focusing on the unique challenges associated with operating optical equipment in a railway environment, such as contamination, power sources and lighting. This also discusses the most common mounting arrangements for camera hardware, including rolling-stock, satellites and way-side cameras. Next, image processing algorithms are discussed, comparing classical approaches and more modern artificial intelligence approaches, for example You Only Look Once (YOLO) and Region-Based Convolutional Neural Network (R-CNN). Then the most common applications for computer vision in the rail industry are analysed. First the track is studied considering computer vision analysis for the detection of different types of rail surface defects on plain line and turnouts, fastener defects, concrete track slab cracking and ballast particle characterisation. Next, the overhead line equipment is considered with applications related to detecting contact loss between pantograph and contact wire, stagger behaviour and defective catenary components. This is followed by discussion of other applications such as rail tunnelling subsidence, tunnel inspection, level crossings, trespass and on-track safety hazards. Finally, opportunities for future research are discussed such as hyperspectral imaging and generative AI, along with possible frontier technologies such as quantum computing
Cohort profile: characterisation, determinants, mechanisms and consequences of the long-term effects of COVID-19 – providing the evidence base for health care services (CONVALESCENCE) in the UK
Get PDFPurpose: The pathogenesis of the long-lasting symptoms which can follow an infection with the SARS-CoV-2 virus (‘long covid’) is not fully understood. The ‘COroNaVirus post-Acute Long-term EffectS: Constructing an evidENCE base’ (CONVALESCENCE) study was established as part of the Longitudinal Health and Wellbeing COVID-19 UK National Core Study. We performed a deep phenotyping case-control study nested within two cohorts (the Avon Longitudinal Study of Parents and Children and TwinsUK) as part of CONVALESCENCE.
Participants: From September 2021 to May 2023, 349 participants attended the CONVALESCENCE deep phenotyping clinic at University College London. Four categories of participants were recruited: cases of long covid (long covid(+)/SARS-CoV-2(+)), alongside three control groups: those with neither long covid symptoms nor evidence of prior COVID-19 (long covid(-)/SARS-CoV-2(-); control group 1), those who self-reported COVID-19 and had evidence of SARS-CoV-2 infection, but did not report long covid (long covid(-)/SARS-CoV-2(+); control group 2) and those who self-reported persistent symptoms attributable to COVID-19 but no evidence of SARS-CoV-2 infection (long covid(+)/SARS-CoV-2(-); control group 3). Remote wearable measurements were performed up until February 2024.
Findings to date: This cohort profile describes the baseline characteristics of the CONVALESCENCE cohort. Of the 349 participants, 141 (53±15 years old; 21 (15%) men) were cases, 89 (55±16 years old; 11 (12%) men) were in control group 1, 75 (49±15 years old; 25 (33%) men) were in control group 2 and 44 (55±16 years old; 9 (21%) men) were in control group 3.
Future plans: The study aims to use a multiorgan score calculated as the cumulative total for each of nine domains (ie, lung, vascular, heart, kidney, brain, autonomic function, muscle strength, exercise capacity and physical performance). The availability of data preceding acute COVID-19 infection in cohorts may help identify the consequences of infection independent of pre-existing subclinical disease and also provide evidence of determinants that influence the development of long covid
Impact of intensity standardisation and ComBat batch size on clinical-radiomic prognostic models performance in a multi-centre study of patients with glioblastoma
Get PDFPurpose
To assess the effect of different intensity standardisation techniques (ISTs) and ComBat batch sizes on radiomics survival model performance and stability in a heterogenous, multi-centre cohort of patients with glioblastoma (GBM).
Methods
Multi-centre pre-operative MRI acquired between 2014 and 2020 in patients with IDH-wildtype unifocal WHO grade 4 GBM were retrospectively evaluated. WhiteStripe (WS), Nyul histogram matching (HM), and Z-score (ZS) ISTs were applied before radiomic feature (RF) extraction. RFs were realigned using ComBat and minimum batch size (MBS) of 5, 10, or 15 patients. Cox proportional hazards models for overall survival (OS) prediction were produced using five different selection strategies and the impact of IST and MBS was evaluated using bootstrapping. Calibration, discrimination, relative explained variation, and model fit were assessed. Instability was evaluated using 95% confidence intervals (95% CIs), feature selection frequency and calibration curves across the bootstrap resamples.
Results
One hundred ninety-five patients were included. Median OS = 13 (95% CI: 12–14) months. Twelve to fourteen unique MRI protocols were used per MRI sequence. HM and WS produced the highest relative increase in model discrimination, explained variation and model fit but IST choice did not greatly impact on stability, nor calibration. Larger ComBat batches improved discrimination, model fit, and explained variation but higher MBS (reduced sample size) reduced stability (across all performance metrics) and reduced calibration accuracy.
Conclusion
Heterogenous, real-world GBM data poses a challenge to the reproducibility of radiomics. ComBat generally improved model performance as MBS increased but reduced stability and calibration. HM and WS tended to improve model performance
Rapid Establishment and Impact Assessment of the Redclaw Crayfish (Cherax quadricarinatus) Invasion in the Kruger National Park, South Africa
Get PDFAmidst the rapid degradation of the environment, protected areas act as a buffer for sensitive species against drivers of change. The Kruger National Park, in the Zambezian Lowveld Freshwater Ecoregion, encompasses two critical transboundary river basins, which are threatened by overexploitation, climate change and nonnative invasive species. We complete an assessment of the abundance, distribution, spread and potential impacts of the invasive redclaw crayfish on community assemblages throughout the five main rivers of the Kruger National Park and compare them to other invasive populations in Southern Africa. Redclaw crayfish have established populations in the Crocodile River and the Sabie-Sand River and are spreading at a rate of 7–8 km/year downstream and 3 km/year upstream. Abundance is lower than the more established invasions, but based on other trajectories, we can expect a tenfold increase in the next 5 years. No impact of crayfish presence or abundance was detected on fish or macroinvertebrate community assemblages. This suggests that as crayfish abundance is still relatively low, there may be a window of opportunity for targeted management. Management options in the rivers of the Kruger National Park are fraught with practical issues due to dangerous megafauna, but further understanding of the role of environmental flows on the establishment capacity of redclaw crayfish may hold some potential. Preventing new incursions into the protected area from watersheds originating outside of the park will need strategic multiorganisational collaboration
Virological surveillance of bats in Southern Kazakhstan
Get PDFBats are known as an important natural reservoir of many viral infections, from which transmission into the human population occurs. This article aimed to examine bats in Kazakhstan for possible circulation of viruses dangerous to humans and other animals. Two hundred sixty samples, including nasal and rectal swabs and blood sera, were collected from bats in southern Kazakhstan. Studies of the bat virome applying high-throughput sequencing revealed the presence of five large families: Circoviridae, Parvoviridae, Retroviridae, Adenoviridae, and Orthoherpesviridae. All of them were found in southern Kazakhstan from Myotis blythii adult individuals of both sexes. Genomic studies of bat herpesviruses have shown that they are potentially representatives of novel species, genetically different from existing ones. Their epidemic potential for humans and other animals requires further research. Serological studies for possible circulation of antibodies to coronaviruses and influenza A viruses have shown negative results, indicating the absence of antibodies in the tested samples. The results demonstrate the need for more profound research to identify the relationship between human and bat viruses in the future
Transforming Assessment: the 2025 Global Research Council survey of funder approaches to responsible research assessment
Get PDFA role for class I p21-activated kinases in the regulation of the excitability of the actin cytoskeleton
Get PDFThe p21-activated kinases (PAKs) are involved in a range of functions, including the regulation of the actin cytoskeleton. However, although many PAK substrates identified have been implicated in the regulation of the actin cytoskeleton, a coherent picture of the total effect of PAK activation on the state of the actin cytoskeleton is unclear. Here, we show that, in mouse embryonic fibroblasts, inhibition of class I PAK kinase activity by small-molecule inhibitors leads to the constitutive production of the phosphoinositide phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3] on the ventral surface of the cell. The formation of patches of PI(3,4,5)P3 remodels the actin cytoskeleton and polarises the cell. From the overexpression of truncated and mutated PAK1 and PAK2 constructs, as well as an in vitro model of PAK activation, we propose that this is driven by a hyper recruitment of class I PAK and PAK-binding partners. This aberrant production of PI(3,4,5)P3 suggests that, by limiting its own recruitment, the kinase activity of class I PAKs acts to downregulate phosphoinositide 3-kinase (PI3K) activity, further highlighting class I PAKs as regulators of PI3K activity and therefore the excitability of the actin cytoskeleton
The impact of e-cigarette use on periodontal health: a systematic review and meta-analysis
Get PDFBackground
Electronic Nicotine Delivery Systems (ENDS, e-cigarettes) are a popular alternative to traditional tobacco smoking. Objective: To evaluate the effect of ENDS use on periodontal health.
Methods
A protocol was published in accordance with PRISMA standards. Subjects with periodontal health, gingivitis and periodontitis were included. Reviews, case reports, letters, abstracts, narratives and expert opinions were excluded. Databases searched included PubMed, Embase, Web of Science, CINAHL Plus, and Dentistry & Oral Sciences Source up until February 2024. Risk of bias was evaluated using the Newcastle-Ottawa Scale, ROBINS-I and the RoB 2 tools.
Results
40 eligible studies were included. Smokers had poorer clinical outcomes than ENDS users and non-smokers/former smokers, apart from bleeding on probing and gingival indices. There was no difference between ENDS users and non-smokers/former smokers in markers of periodontal destruction (pocket probing depths/marginal bone loss). ENDS users had higher plaque scores than non-smokers/former smokers. ENDS use leads to unique microbial changes compared to tobacco smokers and higher pro-inflammatory markers compared to non-smokers/former smokers.
Conclusion
Within the limitations of the included studies which are at high risk of bias, we found evidence that ENDS use had some impact on periodontal parameters compared to non-smokers/former smokers. Tobacco smokers had consistently worst outcomes.
Registration PROSPERO 2024
CRD42024496560
Psychosocial correlates of seizure severity in adults with functional/dissociative seizures (FDS): a systematic review
No full textObjectives
The severity of functional / dissociative seizures (FDS) is commonly explored in the literature, with a recent review identifying it as the second most frequently used seizure-specific measure in FDS outcome studies. In this review, we examine available evidence for factors associated with FDS severity and discuss how this concept has been measured.
Methods
A systematic search was performed in July 2023 (repeated in April 2024) across four databases (PsycInfo, MEDLINE, CINAHL and Cochrane Reviews). Eligible studies were subjected to quality assessment using an adapted version of the Appraisal Tool for Cross-Sectional Studies (AXIS) or the CASP Cohort Study Checklist. Findings were narratively synthesised.
Results
Twelve articles met the inclusion criteria; eleven cross-sectional and one cohort study. Eleven different methodological approaches capturing FDS severity were identified. No studies were primarily designed to explore correlates of FDS severity. Correlates were grouped thematically and ordered based on the number of studies contributing to each theme. Weak to moderate correlations were found within the domains of trauma, mental health, emotional processes, relational, illness perception, symptom attribution, and demographics.
Conclusions
In the absence of validated measures of FDS severity, researchers have used a variety of tools to capture this clinical feature. The range of correlations found for different measures provide initial support for the conceptual validity of FDS severity measures as a treatment outcome and a rationale for the development and validation of an FDS-specific seizure severity measure
Data sources:
Access Repository Dashboard
Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇