Liquid migration in shear thickening suspensions flowing through constrictions

Dense particulate suspensions often become more dilute as they move downstream through a constriction. We find that as a shear-thickening suspension is extruded through a narrow die and undergoes such liquid migration, the extrudate maintains a steady concentration $\phi_c$, independent of time or initial concentration. This concentration $\phi_c$ varies with volumetric flow rate $Q$ and die radius $r_{\rm d}$, but at low $Q$ collapses onto a universal function of $Q/r_{\rm d}^3$, a characteristic shear rate in the die. We explain quantitatively the onset of liquid migration in extrusion by coupling a recent model for discontinuous shear thickening and the `suspension balance model' for solvent permeation through particles.Comment: 5 pages, 5 figure

The impact of the COVID-19 pandemic on self-harm and suicidal behaviour: a living systematic review

Background: The COVID-19 pandemic has caused widespread morbidity and mortality as well as disruption to people’s lives and livelihoods around the world; this has occurred as a result of both infection with the virus itself and the health protection measures taken to curb its spread. There are concerns that rates of suicide, suicidal behaviours and self-harm may rise during and in the aftermath of the pandemic. Given the likely rapidly expanding research evidence base on the pandemic’s impact on rates of suicide, suicidal behaviours and self-harm and emerging evidence about how best to mitigate such effects, it is important that the best available knowledge is made readily available to policymakers, public health specialists and clinicians as soon as is possible. To facilitate this, we plan to undertake a living systematic review focusing on suicide prevention in relation to COVID-19.Method: Regular automated searches will feed into a web-based screening system which will also host the data extraction form for included articles. Our eligibility criteria are wide and include aspects of incidence and prevalence of suicidal behaviour, effects of exposures and effects of interventions in relation to the COVID-19 pandemic, with minimal restrictions on the types of study design to be included. The outcomes assessed will be death by suicide; self-harm or attempted suicide (including hospital attendance and/or admission for these reasons); and suicidal thoughts/ideation. There will be no restriction on study type, except for single case reports. There will be no restriction on language of publication. The review will be updated at three-monthly intervals if a sufficient volume of new evidence justifies doing so.Conclusions: Our living review will provide a regular synthesis of the most up-to-date research evidence to guide public health and clinical policy to mitigate the impact of COVID-19 on suicide.Protocol registration: PROSPERO CRD42020183326 01/05/202

Differential modes of DNA binding by mismatch uracil DNA glycosylase from Escherichia coli: implications for abasic lesion processing and enzyme communication in the base excision repair pathway

Mismatch uracil DNA glycosylase (Mug) from Escherichia coli is an initiating enzyme in the base-excision repair pathway. As with other DNA glycosylases, the abasic product is potentially more harmful than the initial lesion. Since Mug is known to bind its product tightly, inhibiting enzyme turnover, understanding how Mug binds DNA is of significance when considering how Mug interacts with downstream enzymes in the base-excision repair pathway. We have demonstrated differential binding modes of Mug between its substrate and abasic DNA product using both band shift and fluorescence anisotropy assays. Mug binds its product cooperatively, and a stoichiometric analysis of DNA binding, catalytic activity and salt-dependence indicates that dimer formation is of functional significance in both catalytic activity and product binding. This is the first report of cooperativity in the uracil DNA glycosylase superfamily of enzymes, and forms the basis of product inhibition in Mug. It therefore provides a new perspective on abasic site protection and the findings are discussed in the context of downstream lesion processing and enzyme communication in the base excision repair pathway

Migrations in our common home: Responding with care - Ireland's response to the Ukrainian crisis

Policy Brief produced by the Roundtable on Migrations in Our Common HomeIreland’s response to the Ukrainian migrants has been almost exemplary and this “human rights first” approach should be the blueprint for a reshaping of Ireland’s International Protection system. Beyond the immediate challenges faced by Ukrainian people forcibly displaced, the wider geopolitical impacts of the crisis – the dependency on Russian fossil fuel production and resultant risks, together with risks to food security – will be felt globally into the future, and disproportionately impact those who can least absorb them. Ireland needs to focus on the care, human rights and wellbeing of all. The legitimate expectations of people living in Ireland are not being met. This is most obvious in areas such as housing and homelessness, a two-tier healthcare system, the deepening rural-urban divide, and high levels of poverty and social exclusion, especially among children. These are all areas that must be grappled with in addition to our response to the Ukrainian crisis. This policy briefing takes a look at the key issues and makes a series of policy recommendations aimed at addressing immediate and future challenges

Migrations in our common home: Planning for change - Climate change and migration

Policy briefing on Ireland's response to climate migration in the context of COP27Migration linked to climate change did not get the attention it deserves at COP27. The Global North must accept responsibility for its role in driving climate change and abide by their commitments made to schemes which address worsening conditions for those in the Global South – according to the Roundtable on Migration in Our Common Home. COP27 marks thirty years since the adoption of the United Nations Framework Convention on Climate Change. As the world grapples with the devastating consequences of intensifying climate change, this policy brief examines how climate change is impacting migration, displacement and food security. As COP27 draws to a close, this policy brief looks at the pledges made by Ireland, as well as Ireland’s obligations to Official Development Assistance (ODA) and Climate Finance and the compelling argument in favour of Loss and Damage funding made by the Global south for over three decades. As COP27 draws to a close, the Roundtable expresses its disappointment at the lack of ambition evident in Ireland’s response and the repackaging of previously announced, and inadequate, policies

Use Of Medical Tourism For Hip And Knee Surgery In Osteoarthritis: A Qualitative Examination Of Distinctive Attitudinal Characteristics Among Canadian Patients

Background Medical tourism is the term that describes patients’ international travel with the intention of seeking medical treatment. Some medical tourists go abroad for orthopaedic surgeries, including hip and knee resurfacing and replacement. In this article we examine the findings of interviews with Canadian medical tourists who went abroad for such surgeries to determine what is distinctive about their attitudes when compared to existing qualitative research findings about patients’ decision-making in and experiences of these same procedures in their home countries. Methods Fourteen Canadian medical tourists participated in semi-structured phone interviews, all of whom had gone abroad for hip or knee surgery to treat osteoarthritis. Transcripts were coded and thematically analysed, which involved comparing emerging findings to those in the existing qualitative literature on hip and knee surgery. Results Three distinctive attitudinal characteristics among participants were identified when interview themes were compared to findings in the existing qualitative research on hip and knee surgery in osteoarthritis. These attitudinal characteristics were that the medical tourists we spoke with were: (1) comfortable health-related decision-makers; (2) unwavering in their views about procedure necessity and urgency; and (3) firm in their desires to maintain active lives. Conclusions Compared to other patients reported on in the existing qualitative hip and knee surgery literature, medical tourists are less likely to question their need for surgery and are particularly active in their pursuit of surgical intervention. They are also comfortable with taking control of health-related decisions. Future research is needed to identify motivators behind patients’ pursuit of care abroad, determine if the attitudinal characteristics identified here hold true for other patient groups, and ascertain the impact of these attitudinal characteristics on surgical outcomes. Arthritis care providers can use the attitudinal characteristics identified here to better advise osteoarthritis patients who are considering seeking care abroad

An ancient dental gene network regulates development and continuous regeneration of teeth in sharks

The appearance of toothed vertebrates has proven a major determinant of the overall success of this lineage. This is most apparent in sharks and rays (elasmobranchs), which further retain the capacity for life-long tooth regeneration. Given their comparatively basal phylogenetic position, elasmobranchs therefore offer the opportunity for crucial insights into putative ancestral characters of tooth development, yet despite their evolutionary significance this remains poorly understood. Using the established chondrichthyan model, the catshark (Scyliorhinus sp.), we identified the expression of genes representative of conserved signaling pathways during stages of early dental competence, tooth initiation and regeneration. The expression patterns of β-catenin, shh, bmp4, pax9, pitx1/2, and the stem cell marker Sox2, characterise an ancestrally conserved gene set deployed during initiation of the elasmobranch dentition, suggesting that all vertebrate dentitions are defined by the expression of this core set of genes. These findings provide novel evidence to support the conservation in deep evolutionary time of a core set of dental patterning genes, therefore further defining the evolutionary trajectory of tooth development. We show how these genes facilitate the emergence of the shark dentition and offer insights into their deployment during development of the dental lamina, a sheet of dental epithelial cells that are responsible for continuous tooth regeneration. This study further promotes a specific experimental agenda to further characterise the roles of these core developmental genes during vertebrate tooth development, and importantly dental regeneration