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Micro-interface slip damping in a compressed coir vibration isolator
Get PDFThe micro-interface slip damping mechanism is insensitive to temperature, making it suitable for applications where the operating environment makes viscoelastic polymers ineffective. Damping material systems that rely on micro-interface slip typically embody randomly disposed interlocking units leading to complex material behaviors. This work studies a compressed coir vibration isolator that provides a lightweight, low cost and environmentally friendly alternative to common polymer devices. Under cyclic loading, it displays highly nonlinear hysteresis and a gradual change in properties based on the load history. The nonlinear hysteresis is captured with a Masing model, which has been shown to provide an adequate phenomenological representation of systems with large numbers of miniature stick-slip contacts. This study further explores a new way to enrich the Masing model by encoding time evolution using restoring force or displacement time integral, directly adopted from mem-models, a new family of models transferred from electrical engineering. In addition to using the data from the coir isolator, two additional datasets from clayey soil, another application of micro-interface slip damping, are used to validate the modeling approach
The effect of staging of fluidic oscillation on microbubble generation in viscous liquids
Get PDFMicrobubbles are broadly defined as gas–liquid interfaces smaller than 1 mm and larger than 1 μm. Conventional modes of microbubble generation (ultrasound, ablative technologies, and electrolytic mechanisms) requires large amounts of energy and generate a wide distribution of microbubbles. Fluidic oscillation is an energy-efficient technique used for microbubble generation capable of generating a fairly monodisperse population of microbubbles compared to conventional bubbling. This study hypothesises that partial liquid wetting of membrane pores further benefits microbubble production. The partial liquid wetting can be introduced by utilising the ‘off’ portion of the fluidic oscillator, resulting in liquid imbibition. This liquid imbibition temporarily changes the membrane dynamics with intrapore wetting by the liquid. Therefore, using steady flow immediately after this operation would result in a similar behaviour (smaller bubble size) temporarily. This results in an interesting interplay between the two conditions—conventional bubbling (steady flow) and oscillatory flow, thereby presenting an intermediate condition with an associated reduction in bubble size when staged appropriately, i.e., for steady flow bubbling post-fluidic oscillator application. The resultant average bubble size is 25% lower than the steady flow bubbling prior to fluidic oscillation application but is dependent on physico-chemical properties: primarily viscosity and wetting angle. An intermediary condition is set based on the staging resulting in a 25–50% reduction in bubble size from steady-flow dynamics post-application of the oscillatory flow
Pneumolysin-dependent and independent non-canonical autophagy processes mediate host defense against pneumococcal infection
Get PDFStreptococcus pneumoniae is an opportunistic pathogen responsible for life-threatening diseases including pneumonia and meningitis. The host defense against pneumococci relies heavily on macrophages, which can effectively internalize and degrade bacteria. Recent studies have implicated both canonical and non-canonical autophagy-related processes in bacterial clearance, but the precise pathways mediating defense against S. pneumoniae remain unknown. Here, we utilize a well-established zebrafish larval infection model to investigate the role of autophagy in host defense against pneumococci in vivo. Using a transgenic macroautophagy/autophagy reporter line, we found the autophagy marker Map1lc3/Lc3 being recruited to pneumococci-containing vesicles upon bacterial internalization by zebrafish macrophages. The genetic inhibition of core autophagy gene atg5 led to loss of the Lc3 associations and their impaired acidification, significantly delaying bacterial clearance. This Lc3 recruitment is partially mediated by LC3-associated phagocytosis (LAP), as knockdown of cyba and rubcn moderately reduced Lc3 association with phagosomes and diminished pneumococcal degradation. Interestingly, we observed no involvement of xenophagy components in S. pneumoniae-infected macrophages, suggesting the activation of another non-canonical autophagy pathway, distinct from LAP, targeting pneumococci-containing phagosomes. Instead, we found that the pneumococcal pore-forming toxin pneumolysin induces ROS-independent CASM pathways, one of which is abolished by knockdown of tecpr1a indicating the involvement of sphingomyelin-Tecpr1-induced LC3 lipidation (STIL). Collectively, our observations shed new light on the host immune response against S. pneumoniae, demonstrating that several distinct non-canonical autophagy pathways mediate bacterial degradation by macrophages and providing potential targets for the development of novel therapies to combat pneumococcal infections.Abbreviations: ATG: autophagy related; BMDM: bone marrow-derived macrophage; CASM: conjugation of ATG8 to single membranes; CFU: colony-forming units; Cyba: cytochrome b-245, alpha polypeptide; DPI: diphenyleneiodonium, GFP: green fluorescent protein; hpf: hours post-fertilization; hpi: hours post-infection; LAP: LC3-associated phagocytosis; Map1lc3/Lc3: microtubule-associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; NADPH: nicotinamide adenine dinucleotide phosphate; Optn: optineurin; PINCA: pore-forming toxin-induced non-canonical autophagy; Ply: pneumolysin; ROS: reactive oxygen species; SLR: sequestosome-like receptors; Sqstm1: sequestosome 1; STIL: sphingomyelin-TECPR1-induced LC3 lipidation; Tecpr1: tectonin beta-propeller repeat containing 1
Observational ozone datasets over the global oceans and polar regions (version 2024)
Get PDFStudying tropospheric ozone over the remote areas of the planet, such as the open oceans and the polar regions, is crucial to understand the role of ozone as a global climate forcer and regulator of atmospheric oxidative capacity. A focus on the pristine oceanic and polar regions complements the available land-based datasets and provides insights into key photochemical and depositional loss processes that control the concentrations and spatiotemporal variability in ozone as well as the physicochemical mechanisms driving these patterns. However, an assessment of the role of ozone over the oceanic and polar regions has been hampered by a lack of comprehensive observational datasets. Here, we present the first comprehensive collection of ozone data over the oceans and the polar regions. The overall dataset consists of 77 ship cruises/buoy-based observations and 48 aircraft-based campaigns. The dataset, consisting of more than 630 000 independent ozone measurement data points covering the period from 1977 to 2022 and an altitude range from the surface to 5000 m (with a focus on the lowest 2000 m), allows systematic analyses of the spatiotemporal distribution and long-term trends over the 11 defined ocean/polar regions. The datasets from ships, buoys, and aircraft are complemented by ozonesonde data from 29 launch sites or field campaigns and by 21 non-polar and 17 polar ground-based station datasets. The datasets contain information on how long the observed air masses were isolated from land, as estimated by backward trajectories from the individual observation points. To extract observations representative of oceanic conditions, we recommend using a subset of the data with an isolation time of 72 h or longer, from the analysis with coincident radon observations. These filtered oceanic and polar data showed typically flat diurnal cycles at high latitudes, whereas daytime decreases in ozone (11 %–16 %) were observed at lower latitudes. The ship/buoy- and aircraft-based datasets presented here will supplement the land-based ones in the TOAR-II (Tropospheric Ozone Assessment Report Phase II) database to provide a fully global assessment of tropospheric ozone. The described dataset is available at https://doi.org/10.17596/0004044 (Kanaya et al., 2025)
Teachers' discursive constructions of adolescent sexting, consent and gender
Get PDFSexting is the exchange of sexually suggestive content through technological means. Despite being tasked with addressing such incidents in schools, teachers are underrepresented in sexting research. The present study explores teachers' discursive constructions of sexting, consent and gender using Critical Discursive Psychology, analysing 30 interviews with educators and safeguarding staff. The first key finding uncovers the interpretative repertoire of ‘Sexting as a threat’. This repertoire showcases the gendered positions teachers assign adolescents to, positioning ‘Boys as oppressors; girls as victims of sexting’, with girls being simultaneously constructed as sexting to attract boys' attention through the ‘Girls as the validation-seeking Other’ position. Regarding consent, we explicate three repertoires: ‘Consent as an oxymoron in relation to non-consensual distribution’, ‘Consent as illegal’ and ‘Coercion as a power imbalance’. We contextualise and discuss these findings within the socio-political discursive terrain. We highlight their ideological implications and the need to initiate emancipatory positions and discussions regarding inclusive sexting education. Please refer to the Supplementary Material section to find this article's Community and Social Impact Statement
What combination of interventions can optimise HIV prevention for adolescent girls and young women? Cohort analysis of DREAMS participation in urban and rural Kenya
Get PDFComprehensive intervention packages are recommended to address multiple sources of HIV risk for adolescent girls and young women (AGYW). DREAMS is a multi-component HIV prevention program designed to reduce HIV incidence among AGYW. We conducted a prospective cohort study among AGYW aged 13–22 years, randomly selected in rural Gem and urban Nairobi informal settlements followed from 2017/2018–2019. AGYW were classified into three groups: (1) invited to DREAMS and received a “complete” package, (2) invited and received a “partial” package, or (3) not invited to DREAMS. We defined the “complete” package as 4–5 primary interventions in Gem and 5 in Nairobi: the “partial” package as 3 specific interventions in Gem and any 3–4 interventions in Nairobi. We used propensity score-adjusted logistic regression to estimate the causal effect of DREAMS on outcomes under three counterfactual scenarios: all AGYW accessed the complete package, all accessed a partial package, or none were invited. In Nairobi, 1081 AGYW were enrolled. By 2019, 26% accessed the complete package and 32% accessed the partial package. Among those receiving the complete package, there was increase in HIV status knowledge(24.8% [95%CI:16.4,32.6]),social support(13.9% [95%CI:3.3,23.6]) and self-efficacy(10.3% [95%CI:0.5,20.4]) and a decrease in the proportion with ≥2 lifetime partners(-8.0% [95%CI:-15.9,0.0]). In Gem, 1171 AGYW were enrolled. By 2019, 24% received the complete package and 21% received the partial package. We found evidence of an increase in HIV status knowledge(10.0% [95%CI:4.5,15.2]), social support(27.2% [95%CI:19.2,35.5]) and a decrease in condomless sex(-9.1% [95%CI:-13.6,-4.1]), and the proportion with ≥2 lifetime partners(-7.6% [95%CI:-12.4,-2.2]) for the complete package. Among those receiving the partial package, there was a decrease in condomless sex(-12.2% [95%CI: -17.0,-6.4]), and an increase in self-efficacy(8.0% [95%CI:0.0,17]). A package of 4–5 primary DREAMS interventions had positive impacts on multiple HIV-related outcomes in both settings. A partial package was effective in Gem, but not in Nairobi, suggesting the need for context-specific intervention strategies
Thousand cuts: a realistic route to decarbonise the UK cement and concrete sector by 2050
Get PDFTo meet net-zero CO2 targets by 2050, the United Kingdom (UK)’s cement and concrete sector must implement decarbonisation strategies of different readiness levels and effectiveness. These strategies have been presented thoroughly in UK and European Union decarbonisation roadmaps. However, it is challenging to predict, with confidence, whether the UK's 2050 net-zero targets are achievable. This study aims to balance the expectations placed on low-maturity (LM) and high-maturity (HM) strategies such as utilising a lower clinker factor and the use of carbon capture technologies respectively to determine a realistic route in which the UK can reach net-zero targets through a decomposition analysis of each strategy. The sector's carbon emissions were determined by performing a material flow analysis and life cycle assessment. The results showed that by 2050, 11 MtCO2eq/yr is expected to be emitted in 2050 under the business-as-usual scenario. HM strategies have an abatement potential of 4.2 MtCO2eq/yr, while LM strategies are expected to abate 3.4 MtCO2eq/yr. However, LM strategies are limited by industry's willingness to shift from current practices, while the implementation of HM strategies are impeded by financial and resource constraints. Accordingly, it is improbable for the sector to meet UK net-zero carbon targets with confidence unless the yearly concrete demand is reduced by 40 %. To enable the maximum potential of reusing the UK's building stock, direct public incentives, shifts in economic models and policy frameworks are needed
Pilot study to investigate sleep and breathing related complications in children and young people with osteogenesis imperfecta
Get PDFBackground
Children with the rare bone disease osteogenesis imperfecta (OI) suffer from difficulty sleeping, and breathing problems during sleep, which can affect their long-term physical and mental health, and consequently their quality of life. In addition, children and young people with OI have structural and soft tissue changes which could affect breathing both during sleep and in relation to lung function.
Although commonly reported, we do not fully understand how many children are affected, the specific causes (and hence the most effective treatment) and how best to identify these sleep related breathing problems.
Our aim was to assess the feasibility of undertaking a clinical study that would investigate the frequency, severity and potential causes of sleep and breathing related problems in children with OI.
Methods
Twelve children aged 4 to 16 years with a diagnosis of osteogenesis imperfecta attending Sheffield Children’s Hospital were recruited to a prospective observational study. All participants underwent demographic history, quality of life questionnaires, spirometry and overnight in-laboratory polysomnography (PSG) during a 20-month period.
Results
Recruitment targets were reached, and all investigational procedures were well tolerated by children and young people with OI. Clinically abnormal findings from polysomnography (sleep disordered breathing, excessive leg movements and delayed sleep latency) and from spirometry (restrictive airways disease) were identified in seven out of twelve participants who were referred on for further sleep and respiratory investigations. In addition, quality of life of children and young people with OI was lower than the population norms and children with other long-term conditions. These findings justify the need for a larger study, and highlighted some areas for improvement to the methodology for incorporation into future study designs.
Conclusion
It is feasible to carry out a study investigating sleep and breathing problems safely in children with all severities of OI. This feasibility study supports the need for a multicentre trial to investigate this further, with the potential to improve clinical care
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