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Image-based finite element modelling of fibre dynamics in polyester staple spun yarns
No full textThis paper introduces an innovative finite element (FE) modelling approach for fibre dynamics in a staple spun yarn based on the geometrical model derived from X-ray microcomputed tomography (μCT) images. The FE model retains crucial in situ information on fibre anisotropy, length, and continuity while employing advanced stitched scanning technique to reconstruct a 15mm yarn length containing individual fibres with ∼10μm diameter. The research focuses on 100% polyethylene terephthalate (PET) staple ring-spun yarn as a case study, conducting both single fibre and yarn tensile tests to characterise material properties and validate the FE model, respectively. Beyond examining the mechanical response at the yarn level, the model facilitates the investigation of individual fibre’s tensile stress, frictional forces, and extent of migration, thereby enhancing the understanding of fibre interactions during yarn tensile loading. Furthermore, the model enables parametric studies through manipulation of inter-fibre friction coefficients allowing assessment of their impact on overall mechanical behaviour. This innovative modelling approach demonstrates significant potential for exploring the constitutive and failure mechanisms for formation of microplastics from textiles and textile materials in general as well as fibre-reinforced composites. It addresses the critical research gaps in simulating anisotropic behaviours of materials containing textile fibres, paving the way for advanced material design and analysis in materials science and engineering
A novel wavelet energy feature for damage identification with a digital twin considering measurement uncertainties
No full textIn structural health monitoring and damage identification literature, supervised machine learning has been commonly adopted. However, the establishment of the training dataset remains to be an open question. Besides indirect experimental methods such as adding masses, the use of a digital replica (digital twin) in a reference, undamaged state is deemed to be a necessity, so that a variety of future damaged states may be generated by varying the properties of the digital twin. However, little research has been available in the literature that addresses the challenge of the modelling errors in such an approach. This study advances the digital-twin-based damage identification approach by examining the ability of a digital twin to generate the wavelet packet node energy (WPNE) features for a variety of damage states and identifying the influences of inherent uncertain physical properties, particularly damping. A novel WPNE feature is developed through feature engineering, effectively mitigating inaccuracies brought about in the damping estimates. The proposed digital-twin-based damage identification approach with the new WPNE feature is validated via numerical and laboratory experiments, demonstrating its robustness against inevitable modelling errors. This work brings the role of digital twins in damage identification a step further towards real-life applications
Copula-based hazard analysis of office buildings exposed to potential earthquake-fire impacts
No full textBuildings in service may be exposed to multiple hazards such as earthquake and fire at the same time. It is important to consider the probability of such hazards as joint events in the risk assessment of buildings. However, there has been a lack of rigorous consideration of fire and earthquake as joint events in the existing literature on multi-hazard analysis of buildings. This paper presents an investigation into the multi-hazard analysis of office buildings exposed to fire-earthquake impacts. A selected region is adopted to illustrate the development of a probabilistic model for the region-specific earthquake intensity, in terms of the peak ground acceleration (PGA). The Gumbel distribution is applied, which can explain 98.3 % of the uncertainty in earthquake intensity for the study area. Additionally, the general fire load density (FLD) is employed as the potential fire-related hazard predictive parameter. The copula method is used to develop the joint probability distribution model for fire-earthquake scenarios in the specific area. In the development of the probability distribution model for the PGA, the recorded PGA data from past earthquakes is used in conjunction with the PGA attenuation function, which is useful for addressing the scarcity of seismic parameters. When the joint probability distribution of the model parameters exceeds 0.5, the joint probability results obtained from the model parameters are advantageous. Therefore, the joint probability should be calculated according to the joint distribution of bivariate discrete random variables for “low probability, high consequence” events. Subsequently, a decision analysis is conducted for multi-hazard events involving earthquakes and fires. The results indicate that for compartments with FLD values in the interval [200, 1000], safety decisions should be structured according to a graded standard. Finally, a steel structure case is included to demonstrate the performance of the structure under earthquake-fire multi-hazard conditions.</p
Whole Genome Sequencing of ‘Mutation-Negative’ Individuals with Cornelia de Lange Syndrome
No full textThis study aimed to assess the diagnostic utility of whole genome sequence analysis in a well-characterised research cohort of individuals referred with a clinical suspicion of Cornelia de Lange syndrome (CdLS) in whom prior genetic testing had not identified a causative variant. Short read, whole genome sequencing was performed in 195 individuals from 105 families, 108 of whom were affected. 100/108 of the affected individuals had prior relevant genetic testing with no pathogenic variant being identified. The study group comprised 42 trios in which both parental samples were available for testing (42 affected individuals and 126 unaffected parents), 61 singletons (unrelated affected individuals) and two families with more than one affected individual. The results showed that 32 unrelated probands from 105 families (30.5%) had likely causative coding region disrupting variants. Four loci were identified in >1 proband: NIPBL (10), ANKRD11 (6), EP300 (3), EHMT1 (2). Single variants were detected in the remaining genes (EBF3, KMT2A, MED13L, NLGN3, NR2F1, PHIP, PUF60, SET, SETD5, SMC1A, TBL1XR1). Possibly causative variants in non-coding regions of NIPBL were identified in four individuals. Single de novo variants were identified in five genes not previously reported to be associated with any developmental disorder: ARID3A, PIK3C3, MCM7, MIS18BP1 and WDR18. Clustering of de novo non-coding variants implicate a single uORF and a small region in intron 21 in NIPBL regulation. Causative variants in genes encoding chromatin-associated proteins, with no defined influence on cohesin function, appear to result in CdLS-like clinical features. This study demonstrates the clinical utility of whole genome sequencing as a diagnostic test in individuals presenting with CdLS or CdLS-like phenotypes
Longitudinal observational (single cohort) study on the causes of trypanocide failure in cases of African animal trypanosomosis in cattle near wildlife protected areas of Northern Tanzania
No full textAfrican animal trypanosomosis (AAT) in cattle is primarily managed through trypanocide administration and insecticide application. Trypanocides can be used for both treatment and prophylaxis, but failure is often reported; this may occur due to resistance, substandard drugs, or inappropriate administration. This study in Tanzania aims to quantify reasons for trypanocide failure. An observational year-long longitudinal study was conducted in high-risk AAT areas in Serengeti District between June 2021-October 2022. Purposive sampling targeted herds with high utilization of the prophylactic trypanocide isometamidium chloride (ISM). When a farmer administered a trypanocide (ISM, diminazine aceturate, homidium), the project veterinarian assessed administration and treatment outcomes were determined based on PCR results from blood samples. A multivariable mixed model was utilized to evaluate risk factors for prophylaxis failure. Quality analysis was performed on trypanocide samples using High Performance Liquid Chromatography. A total of 630 cattle from 21 farms were monitored for a year-long period. A total of 295 trypanocide administrations were reported, predominantly being ISM (56%) used for prophylaxis (87%). One-third of trypanocide administrations were not given adequately, and many trypanocides were given to animals that tested negative for trypanosome infections by PCR. Failures occurred in 7% (95% CI 3.0-14%) of curative treatments, and 44% (95% CI 35-42%) of prophylactic administrations. The brand of ISM was significantly associated with odds of prophylaxis failure (p = 0.011). On quality analysis, two ISM samples had no detectable ISM isomers, but the remainder of ISM and DA samples (n=46) fell within the range of acceptable levels. Drug counterfeiting, inadequate use of trypanocides, and resistance are all contributing to trypanocide failure, limiting effective AAT control and with implications for human disease risk. In order to curb trypanocide failure a multi-modal approach to managing the use of trypanocides is required to address all contributing factors.<br/
The promises and limits of standardisation through paper-based technologies:An ethnographic exploration of integrated management of childhood illness (IMCI) in Bangladesh
No full textIntegrated Management of Childhood Illness (IMCI) is a strategy that aims to standardise clinical assessment and treatment of sick children. In this article, we examine the aspirations and unfolding of introducing a revised IMCI strategy in Bangladesh. We carried out ethnographic fieldwork among project implementors and in IMCI health service delivery settings in Kushtia district, including 36 semi-structured interviews with policymakers, programmers and IMCI service providers. We focused on the IMCI register, a paper-based technology designed to guide health service providers to enact standardised treatment and decision-making during healthcare encounters. During its design, policymakers and programmers aspired to produce a register that would be simple to use and guide health service providers to enact care uniformly. However, simplicity was muddled by the range of agendas and negotiations around what should be standardised and how. In health facility settings, despite national approval, the register's legitimacy was ambiguous as it was perceived as a materialisation of an external project, and its introduction did little to reconfigure how providers enacted health care. However, it operated as a powerful material to make claims about the types of care that matter, as providers saw the work of completing the register as compromising their ability to do the highly valued work of interfacing with patients. Moreover, the register became a tool to negotiate and index intra-institutional hierarchies. Rather than pointing to project failure, these findings reflect the nature of technologies, which are always reconfigured within the systems and social worlds in which they are embedded
Perceived benefits and barriers of gardening amongst urban older adults:A Chinese perspective
No full textExisting research exploring perspectives on gardening has primarily focused on Western populations. The present study, employing qualitative semi-structured interviews with 21 urban-dwelling Chinese older adults, investigated their perceived benefits and barriers to gardening. Reflexive thematic analysis of interview transcripts revealed that urban Chinese older adults perceive gardening as beneficial to their living environment, physical, psychological, and social wellbeing, and as a source of home-grown products. Perceived barriers include the lack of suitable gardening sites, insufficient time and support, difficulties in obtaining materials, the inseparability of gardening and living areas, and low self-efficacy in gardening. Cultural and socially specific influences are reflected in gardening practices, such as plant symbolism, household structures, and residential conditions, highlighting the importance of locally tailored strategies for future gardening programmes
Life-course exposure to air pollution and the risk of dementia in the Lothian Birth Cohort 1936
No full textBackground: Air pollution in later life has been associated with dementia; however, limited research has investigated the association between air pollution across the life course, either at specific life periods or cumulatively. The project investigates the association of air pollution with dementia via a life-course epidemiological approach. Methods: Participants of the Lothian Birth Cohort, born in 1936, provided lifetime residential history in 2014. Participant’s air pollution exposure for time periods 1935, 1950, 1970, 1980, 1990, 2001, and 2007 was modeled using an atmospheric chemistry transport model. Lifetime cumulative exposures were calculated as time-weighted mean exposure. Of 572 participants, 67 developed all-cause dementia [35 with Alzheimer's dementia (AD)] by wave 5 (~82 years). Cox proportional hazards and competing risk models assessed the association between all-cause dementia and AD with particulate matter (diameter of ≤2.5 µm) PM2.5 and nitrogen dioxide (NO2 ) exposure at specific life periods and cumulatively. False discovery rate (FDR) correction was applied for multiple testing. Results: The mean follow-up was 11.26 years. One standard deviation (SD) higher exposure to air pollution in 1935 (PM2.5 = 14.03 μg/m3 , NO2 = 5.35 μg/m3 ) was positively linked but not statistically significant to all-cause dementia [PM2.5 hazard ratio (HR) = 1.16, 95% confidence interval (CI) = 0.90, 1.49; NO2 HR = 1.13, 95% CI = 0.88, 1.47] and AD (PM2.5 HR = 1.38, 95% CI = 1.00, 1.91; NO2 HR = 1.35, 95% CI = 0.92, 1.99). In the competing risk model, one SD elevated PM2.5 exposure (1.12 μg/m3 ) in 1990 was inversely associated with dementia (subdistribution HR = 0.82, 95% CI = 0.67, 0.99) at P = 0.034 but not after FDR correction (PFDR = 0.442). Higher cumulative PM2.5 per one SD was associated with an increased risk of all-cause dementia and AD for all accumulation models except for the early-life model. Conclusion: The in-utero and early-life exposure to PM2.5 and NO2 was associated with higher AD and all-cause dementia risk, suggesting a sensitive/critical period. Cumulative exposure to PM2.5 across the life course was associated with higher dementia risk. Midlife PM2.5 exposure’s negative association with all-cause dementia risk may stem from unaddressed confounders or bias
Estimation of respiratory syncytial virus-associated hospital admissions in five European countries using attribution analysis
Get PDFBackgroundRespiratory syncytial virus (RSV) can cause severe disease, notably among infants, older adults, and individuals with comorbidities. Non-systematic testing and differences in coding practices affect direct measures of the hospital disease burden. We aim to tackle this issue and estimate RSV-associated respiratory hospital admissions through time series modelling of hospital admissions.MethodsThe number of RSV hospital admissions in Denmark, England, Finland, the Netherlands, and Spain were estimated with attribution analyses, using age-specific respiratory tract infection (RTI) admissions combined with virological data, both from routinely collected healthcare data. Analyses covered the years 2016–2023.FindingsThe attributed incidence of RSV per 100,000 children 0–2 months ranged from 1715 in Denmark to 3842 in England. In older adults, substantial differences in the incidence of ICD-10 coded RSV hospitalisations were found, while the attributed RSV incidence was more comparable, ranging from approximately 100 per 100,000 in adults 65–74 years to 200 per 100,000 persons 75–84 years and 500 per 100,000 persons 85 years and older.InterpretationRSV-attributed time series exhibit a high degree of synchronicity between participating countries, suggesting that this method for attribution addresses the known issues with underdiagnosis and misclassification. In the older age groups, a substantial proportion of RTI hospitalisations is attributed to RSV, underscoring the relevance of RSV as a cause of severe respiratory infections
Fluoxetine and fractures after stroke:an individual patient data meta-analysis of three large randomised controlled trials of fluoxetine for stroke recovery
Get PDFBackgroundObservational studies have shown that selective serotonin reuptake inhibitors are associated with an increased risk of bone fractures, but the association can be confounded by indication and other sources of systematic bias that can be minimised in randomised controlled trials (RCTs).AimOur aim was to report the rate, site, context, and predictors of fractures after stroke, and whether the fractures modified the effect of fluoxetine on modified Rankin score (mRS) at six months in an individual patient data meta-analysis of 5907 patients enrolled in three RCTs of fluoxetine (20mg for six months) for stroke recovery. MethodsWe classified fractures by treatment allocation, site (and thus likelihood of osteoporosis) and context, then performed multivariable analyses to explore independent predictors of fractures. We explored whether the trend towards a poorer mRS at 6 months was explained by a fracture excess. Risk of bias was assessed using GRADE.ResultsAmong 5907 patients randomised at a mean of 6.6 days (SD3.6) post-stroke onset and followed for six months, the number of fractures at 6 months was 93 (3.15%) in the fluoxetine group vs 41 (1.39%) in the control group (difference 1.76, 95% CI 0.10 to 2.51). 128 patients with fractures were suitable for further analyses. Of these 102 (80%) were in sites typically affected by osteoporosis; 115 (90%) were associated with falls and one (1%) with a seizure. Independent fracture risk factors were female sex (hazard ratio (HR) 1.96; 95% CI 1.37 to 2.81, p=0.0002), age>70 years (HR 2.30, 95% CI 1.52 to 3.49, p<0.001), previous fractures (HR 0.63 for no previous fractures, 95% CI 0.42 to 0.94, p=0.0227), and randomised treatment (fluoxetine) (HR 2.39; 95% CI 1.64 to 3.49, p<0.001). The common odds ratio for the effect of fluoxetine on mRS at 6 months was unchanged after excluding fracture patients. Risk of bias was high for imprecision.ConclusionFractures were more common in the fluoxetine group but the absolute risk of fractures was small and risk estimates were imprecise. Most fractures occurred with a fall, and in osteoporotic locations. Fractures did not modify the effect of fluoxetine on functional outcome
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