Two-dimensional constriction flows of foams

International audienceThe flow of a quasi-two-dimensionalfoam through a constriction is described. The bubble velocity and elongation (texture) is compared between two sets of experiments and two different quasi-static simulations using Surface Evolver and Potts model. The simulations capture the effect of changing the degree of rounding of the corners of the flow geometry and the length of the constricted region. Validation of these simulation methods offers the possibility to easily vary many parameters of interest and to explore parameter ranges that are inaccessible to experiments such as low liquid fraction and slow velocity. Perspectives include characterisations of a 3D flow at the bubble scale

Exacerbated inflammatory arthritis in response to hyperactive gp130 signalling is independent of IL-17A

Objective Interleukin (IL)-17A producing CD4 T-cells (TH-17 cells) are implicated in rheumatoid arthritis (RA). IL-6/STAT3 signalling drives TH-17 cell differentiation, and hyperactive gp130/STAT3 signalling in the gp130F/F mouse promotes exacerbated pathology. Conversely, STAT1-activating cytokines (eg, IL-27, IFN-γ) inhibit TH-17 commitment. Here, we evaluate the impact of STAT1 ablation on TH-17 cells during experimental arthritis and relate this to IL-17A-associated pathology. Methods Antigen-induced arthritis (AIA) was established in wild type (WT), gp130F/F mice displaying hyperactive gp130-mediated STAT signalling and the compound mutants gp130F/F:Stat1−/− and gp130F/F: Il17a−/− mice. Joint pathology and associated peripheral TH-17 responses were compared. Results Augmented gp130/STAT3 signalling enhanced TH-17 commitment in vitro and exacerbated joint pathology. Ablation of STAT1 in gp130F/F mice (gp130F/F: Stat1−/− ) promoted the hyperexpansion of TH-17 cells in vitro and in vivo during AIA. Despite this heightened peripheral TH-17 cell response, disease severity and the number of joint-infiltrating T-cells were comparable with that of WT mice. Thus, gp130-mediated STAT1 activity within the inflamed synovium controls T-cell trafficking and retention. To determine the contribution of IL-17A, we generated gp130F/F:IL-17a−/− mice. Here, loss of IL-17A had no impact on arthritis severity. Conclusions Exacerbated gp130/STAT-driven disease in AIA is associated with an increase in joint infiltrating T-cells but synovial pathology is IL-17A independent

The antibacterial efficacy of a foam mouthwash and its ability to remove biofilms

Abstract Objectives/Aims To evaluate the antimicrobial activity of a newly developed foam mouthwash containing a modified lactoperoxidase system in vitro. Materials and methods Biofilms of five bacterial species were developed on hydrophobic and hydrophilic surfaces whilst salivary-based biofilm was grown on tooth enamel. Each surface was exposed to the foam mouthwash or saline in vitro. Optical density and scanning electron microscopy (SEM) was used to determine retention of the biofilm following 5 or 30 s exposure time. Results The foam mouthwash was active against biofilms formed by S. aureus, K. rhizophila, M. thailandicus, E. coli, and C. violaceum and eliminated significant amount of biofilm from each surface; immature 4 h biofilm was less resistant than 24 h biofilm. A 30 s rinse showed best performance, with removal of up to 66% of biofilm from the hydrophilic surface. SEM imaging confirmed oral biofilm removal from the enamel surface after a 5 s rinse with the foam mouthwash. Discussion Foam mouthwash demonstrated a significant impact on growing biofilm when compared against saline solution. Growing biofilms were more susceptible to the action of the foam mouthwash, which justifies after-meal use of the mouthwash when traditional dentifrices may not be accessible. Conclusions Foam mouthwash can be a convenient on-the-go format of oral care products that can be used after meals or when needed to reduce the risk of biofilm-associated oral conditions

Annual water residence time effects on thermal structure: a potential lake restoration measure?

Innovative methods to combat internal loading issues in eutrophic lakes are urgently needed to speed recovery and restore systems within legislative deadlines. In stratifying lakes, internal phosphorus loading is particularly problematic during the summer stratified period when anoxia persists in the hypolimnion, promoting phosphorus release from the sediment. A novel method to inhibit stratification by reducing residence times is proposed as a way of controlling the length of the hypolimnetic anoxic period, thus reducing the loading of nutrients from the sediments into the water column. However, residence time effects on stratification length in natural lakes are not well understood. We used a systematic modelling approach to investigate the viability of changes to annual water residence time in affecting lake stratification and thermal dynamics in Elterwater, a small stratifying eutrophic lake in the northwest of England. We found that reducing annual water residence times shortened and weakened summer stratification. Based on finer-scale dynamics of lake heat fluxes and water column stability we propose seasonal or sub-seasonal management of water residence time is needed for the method to be most effective at reducing stratification as a means of controlling internal nutrient loading

Can reductions in water residence time be used to disrupt seasonal stratification and control internal loading in a eutrophic monomictic lake?

Anthropogenic eutrophication caused by excess loading of nutrients, especially phosphorus (P), from catchments is a major cause of lake water quality degradation. The release of P from bed sediments to the water column, termed internal loading, can exceed catchment P load in eutrophic lakes, especially those that stratify during warm summer periods. Managing internal P loading is challenging, and although a range of approaches have been implemented, long-term success is often limited, requiring lake-specific solutions. Here, we assess the manipulation of lake residence time to inhibit internal loading in Elterwater, a shallow stratifying lake in the English Lake District, UK. Since 2016, additional inflowing water has been diverted into the inner basin of Elterwater to reduce its water residence time, with the intention of limiting the length of the stratified period and reducing internal loading. Combining eight years of field data in a Before-After-Control-Impact study with process-based hydrodynamic modelling enabled the quantification of the residence time intervention effects on stratification length, water column stability, and concentrations of chlorophyll a and P. Annual water residence time was reduced during the study period by around 40% (4.9 days). Despite this change, the lake continued to stratify and developed hypolimnetic anoxia. As a result, there was little significant change in phosphorus (as total or soluble reactive phosphorus) or chlorophyll a concentrations. Summer stratification length was 2 days shorter and 7% less stable with the intervention. Our results suggest that the change to water residence time in Elterwater was insufficient to induce large enough physical changes to improve water quality. However, the minor physical changes suggest the management measure had some impact and that larger changes in water residence time may have the potential to induce reductions in internal loading. Future assessments of management requirements should combine multi-year observations and physical lake modelling to provide improved understanding of the intervention effect size required to alter the physical structure of the lake, leading to increased hypolimnetic oxygen and reduced potential for internal loading

Comparison of primary care experiences among adults in general outpatient clinics and private general practice clinics in Hong Kong

Abstract. Background. The main goal of Hong Kong's publicly-funded general outpatient clinics (GOPCs) is to provide primary medical services for the financially vulnerable. The objective of the current study was to compare the primary care experiences of GOPC users and the users of care provided by private general practitioners (GPs) in Hong Kong via a territory-wide telephone survey. Methods. One thousand adults in Hong Kong aged 18 and above were interviewed by a telephone survey. The modified Chinese translated Primary Care Assessment Tool was used to collect data on respondents' primary care experience. Results. Our results indicated that services provided by GOPC were more often used by female, older, poorer, chronically-ill and less educated population. GOPC participants were also more likely to have visited a specialist or used specialist services (69.7% vs. 52.0%; p < 0.001), although this difference in utilization of specialist services disappeared after adjusting for age (55.7% vs. 52.0%, p = 0.198). Analyses were also performed to asses the relationship between healthcare settings (GOPCs versus private GPs) and primary care quality. Private GP patients achieved higher overall PCAT scores largely due to better accessibility (Mean: 6.88 vs. 8.41, p < 0.001) and person-focused care (Mean: 8.37 vs. 11.69, p < 0.001). Conclusions. Our results showed that patients primarily receiving care from private GPs in Hong Kong reported better primary care experiences than those primarily receiving care from GOPCs. This was largely due to the greater accessibility and better interpersonal relationships offered by the private GPs. As most patients use both GOPCs and private GPs, their overall primary care experiences may not be as different as the findings of this study imply. © 2010 Wong et al; licensee BioMed Central Ltd.link_to_subscribed_fulltex

International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci.

The risk of posttraumatic stress disorder (PTSD) following trauma is heritable, but robust common variants have yet to be identified. In a multi-ethnic cohort including over 30,000 PTSD cases and 170,000 controls we conduct a genome-wide association study of PTSD. We demonstrate SNP-based heritability estimates of 5-20%, varying by sex. Three genome-wide significant loci are identified, 2 in European and 1 in African-ancestry analyses. Analyses stratified by sex implicate 3 additional loci in men. Along with other novel genes and non-coding RNAs, a Parkinson's disease gene involved in dopamine regulation, PARK2, is associated with PTSD. Finally, we demonstrate that polygenic risk for PTSD is significantly predictive of re-experiencing symptoms in the Million Veteran Program dataset, although specific loci did not replicate. These results demonstrate the role of genetic variation in the biology of risk for PTSD and highlight the necessity of conducting sex-stratified analyses and expanding GWAS beyond European ancestry populations

COVID-19 in congenital heart disease (COaCHeD) study

Background: COVID-19 has caused significant worldwide morbidity and mortality. Congenital heart disease (CHD) is likely to increase vulnerability and understanding the predictors of adverse outcomes is key to optimising care.// Objective: Ascertain the impact of COVID-19 on people with CHD and define risk factors for adverse outcomes.// Methods: Multicentre UK study undertaken 1 March 2020–30 June 2021 during the COVID-19 pandemic. Data were collected on CHD diagnoses, clinical presentation and outcomes. Multivariable logistic regression with multiple imputation was performed to explore predictors of death and hospitalisation.// Results: There were 405 reported cases (127 paediatric/278 adult). In children (age <16 years), there were 5 (3.9%) deaths. Adjusted ORs (AORs) for hospitalisation in children were significantly lower with each ascending year of age (OR 0.85, 95% CI 0.75 to 0.96 (p<0.01)). In adults, there were 24 (8.6%) deaths (19 with comorbidities) and 74 (26.6%) hospital admissions. AORs for death in adults were significantly increased with each year of age (OR 1.05, 95% CI 1.01 to 1.10 (p<0.01)) and with pulmonary arterial hypertension (PAH; OR 5.99, 95% CI 1.34 to 26.91 (p=0.02)). AORs for hospitalisation in adults were significantly higher with each additional year of age (OR 1.03, 95% CI 1.00 to 1.05 (p=0.04)), additional comorbidities (OR 3.23, 95% CI 1.31 to 7.97 (p=0.01)) and genetic disease (OR 2.87, 95% CI 1.04 to 7.94 (p=0.04)).// Conclusions: Children were at low risk of death and hospitalisation secondary to COVID-19 even with severe CHD, but hospital admission rates were higher in younger children, independent of comorbidity. In adults, higher likelihood of death was associated with increasing age and PAH, and of hospitalisation with age, comorbidities and genetic disease. An individualised approach, based on age and comorbidities, should be taken to COVID-19 management in patients with CHD

COVID-19 in congenital heart disease (COaCHeD) study

BACKGROUND: COVID-19 has caused significant worldwide morbidity and mortality. Congenital heart disease (CHD) is likely to increase vulnerability and understanding the predictors of adverse outcomes is key to optimising care.OBJECTIVE: Ascertain the impact of COVID-19 on people with CHD and define risk factors for adverse outcomes.METHODS: Multicentre UK study undertaken 1 March 2020-30 June 2021 during the COVID-19 pandemic. Data were collected on CHD diagnoses, clinical presentation and outcomes. Multivariable logistic regression with multiple imputation was performed to explore predictors of death and hospitalisation.RESULTS: There were 405 reported cases (127 paediatric/278 adult). In children (age &lt;16 years), there were 5 (3.9%) deaths. Adjusted ORs (AORs) for hospitalisation in children were significantly lower with each ascending year of age (OR 0.85, 95% CI 0.75 to 0.96 (p&lt;0.01)). In adults, there were 24 (8.6%) deaths (19 with comorbidities) and 74 (26.6%) hospital admissions. AORs for death in adults were significantly increased with each year of age (OR 1.05, 95% CI 1.01 to 1.10 (p&lt;0.01)) and with pulmonary arterial hypertension (PAH; OR 5.99, 95% CI 1.34 to 26.91 (p=0.02)). AORs for hospitalisation in adults were significantly higher with each additional year of age (OR 1.03, 95% CI 1.00 to 1.05 (p=0.04)), additional comorbidities (OR 3.23, 95% CI 1.31 to 7.97 (p=0.01)) and genetic disease (OR 2.87, 95% CI 1.04 to 7.94 (p=0.04)).CONCLUSIONS: Children were at low risk of death and hospitalisation secondary to COVID-19 even with severe CHD, but hospital admission rates were higher in younger children, independent of comorbidity. In adults, higher likelihood of death was associated with increasing age and PAH, and of hospitalisation with age, comorbidities and genetic disease. An individualised approach, based on age and comorbidities, should be taken to COVID-19 management in patients with CHD.</p