Evaluation and reduction of numerical diffusion effects in viscous aerofoil flow calculations

The Reynolds-averaged Navier-Stokes (RANS) equations form the most accurate model of viscous flow which can currently be solved computationally on a routine basis for practical engineering problems, given the size and cost of present-day computers. Before RANS solution methods can be used with confidence for the design of aircraft components, a number of areas related to solution accuracy must be investigated, one of which is numerical diffusion. Numerical diffusion, arising from the discrete solution method employed, is necessary to ensure numerical stability, but if too much is included the ability to predict physical phenomena (particularly diffusive ones) accurately can be seriously impaired, with obvious implications for the rational assessmenot f turbulence models. The amount of numerical diffusion in solutions of the RANS equations is evaluated in the present work using two currently popular algorithms, for aerofoil flow test cases. The effect of the numerical diffusion on the prediction of physical processes is investigated, as is the behaviour of the numerical diffusion and corresponding solution when grid quality and algorithm smoothing parameters are varied. Results are presented in two ways, line diagrams giving detailed information along individual grid lines, and contour plots (showing a quantity called the Numerical Diffusion Ratio, NDR) giving overall information on accuracy of the solution throughout the field. The level of numerical diffusion in certain parts of the solution is shown to be unacceptably high in a number of cases. Methods for modifying the NDR are investigated, with the aim of making it suitable for use as a "weighting function" for guiding automatic grid adaptation, to improve solution accuracy. It is shown that some of the modified forms of NDR can be used successfully in this manner. The advantages and disadvantages of using such a solution-accuracy measure (as opposed to the usual solution-activity measures) are discussed and some conclusions and recommendations are made

Silencing the cytokine storm: the use of intravenous anakinra in haemophagocytic lymphohistiocytosis or macrophage activation syndrome

The term cytokine storm syndromes describes conditions characterised by a life-threatening, fulminant hypercytokinaemia with high mortality. Cytokine storm syndromes can be genetic or a secondary complication of autoimmune or autoinflammatory disorders, infections, and haematological malignancies. These syndromes represent a key area of interface between rheumatology and general medicine. Rheumatologists often lead in management, in view of their experience using intensive immunosuppressive regimens and managing cytokine storm syndromes in the context of rheumatic disorders or infection (known as secondary haemophagocytic lymphohistiocytosis or macrophage activation syndrome [sHLH/MAS]). Interleukin (IL)-1 is pivotal in hyperinflammation. Anakinra, a recombinant humanised IL-1 receptor antagonist, is licenced at a dose of 100 mg once daily by subcutaneous injection for rheumatoid arthritis, systemic juvenile idiopathic arthritis, adult-onset Still's disease, and cryopyrin-associated periodic syndromes. In cytokine storm syndromes, the subcutaneous route is often problematic, as absorption can be unreliable in patients with critical illness, and multiple injections are needed to achieve the high doses required. As a result, intravenous anakinra is used in clinical practice for sHLH/MAS, despite this being an off-licence indication and route of administration. Among 46 patients admitted to our three international, tertiary centres for sHLH/MAS and treated with anakinra over 12 months, the intravenous route of delivery was used in 18 (39%) patients. In this Viewpoint, we describe current challenges in the management of cytokine storm syndromes and review the pharmacokinetic and safety profile of intravenous anakinra. There is accumulating evidence to support the rationale for, and safety of, intravenous anakinra as a first-line treatment in patients with sHLH/MAS. Intravenous anakinra has important clinical relevance when high doses of drug are required or if patients have subcutaneous oedema, severe thrombocytopenia, or neurological involvement. Cross-speciality management and collaboration, with the generation of international, multi-centre registries and biobanks, are needed to better understand the aetiopathogenesis and improve the poor prognosis of cytokine storm syndromes

How can field margin management contribute to invertebrate biodiversity?

Farmland invertebrates are vital for healthy ecosystem functioning. Many groups have declined due to agricultural intensification. Arable field margins potentially can increase food resources and provide winter refuges for invertebrates. They might also buffer them from agrochemical applications and farm operations. This chapter describes a series of field and farm-scale experiments which show that ways in which arable field margins are established and managed can have profound effects on their invertebrate assemblages. Field margin swards established by sowing with a grass and wildflower seed mixture attracted more butterflies than naturally regenerated swards. In the short term, larger and more species-rich invertebrate assemblages were fostered on unmanaged margins than on those managed by cutting. The timing of cutting was critical, with mid-summer cutting having the most persistent, negative effects on invertebrates, while cutting in spring and autumn was generally less damaging and may help maintain sward species richness. Fallowed land (set-aside) configured as blocks rather than margins constituted qualitatively different habitats for invertebrates. Margin width had complex effects on invertebrate abundance and species richness. Boundary hedgerows increased numbers of most invertebrate groups in the adjacent margin. The chapter suggests that blanket management approaches for invertebrates at the farm scale are not optimal. A diverse farmed landscape, with margins of different sizes and different sward structures, will provide for the different ecological requirements of invertebrate populations, and promote their diversity in the characteristically unstable environment of arable systems

Profiling of Glycan Receptors for Minute Virus of Mice in Permissive Cell Lines Towards Understanding the Mechanism of Cell Recognition

The recognition of sialic acids by two strains of minute virus of mice (MVM), MVMp (prototype) and MVMi (immunosuppressive), is an essential requirement for successful infection. To understand the potential for recognition of different modifications of sialic acid by MVM, three types of capsids, virus-like particles, wild type empty (no DNA) capsids, and DNA packaged virions, were screened on a sialylated glycan microarray (SGM). Both viruses demonstrated a preference for binding to 9-O-methylated sialic acid derivatives, while MVMp showed additional binding to 9-O-acetylated and 9-O-lactoylated sialic acid derivatives, indicating recognition differences. The glycans recognized contained a type-2 Galβ1-4GlcNAc motif (Neu5Acα2-3Galβ1-4GlcNAc or 3′SIA-LN) and were biantennary complex-type N-glycans with the exception of one. To correlate the recognition of the 3′SIA-LN glycan motif as well as the biantennary structures to their natural expression in cell lines permissive for MVMp, MVMi, or both strains, the N- and O-glycans, and polar glycolipids present in three cell lines used for in vitro studies, A9 fibroblasts, EL4 T lymphocytes, and the SV40 transformed NB324K cells, were analyzed by MALDI-TOF/TOF mass spectrometry. The cells showed an abundance of the sialylated glycan motifs recognized by the viruses in the SGM and previous glycan microarrays supporting their role in cellular recognition by MVM. Significantly, the NB324K showed fucosylation at the non-reducing end of their biantennary glycans, suggesting that recognition of these cells is possibly mediated by the Lewis X motif as in 3′SIA-LeX identified in a previous glycan microarray screen

Speech and language therapists' management practices, perceived effectiveness of current treatments and interest in neuromuscular electrical stimulation for acquired dysarthria rehabilitation: an international perspective

Background Research is beginning to shed light on the practices employed by speech-language therapists (SLTs) for the management of acquired dysarthria. However, studies that explore SLTs’ satisfaction with the effectiveness of current therapies and their interest in new treatment methods for this population have not been carried out. One potential new method is neuromuscular electrical stimulation (NMES): the pool of evidence for its use in rehabilitation is increasing, yet it has not been widely explored for use with dysarthria. Aim To extend the understanding of acquired dysarthria management practices employed by SLTs across the globe and determine their satisfaction with current therapy options. To explore their interest in using NMES with this population. Methods and Procedures A cross-sectional international online survey was developed and disseminated to SLTs working with adults with acquired dysarthria through international professional associations. The survey collected information on demographic characteristics, dysarthria management practices, satisfaction with treatment effectiveness and interest in and knowledge of NMES. Survey responses were analysed using descriptive and inferential statistics, and quantitative content analysis. Outcomes and Results A total of 211 SLTs (North America, 48.8%; Europe, 36%; Asia, 8.1%; Oceania, 5.7%; Africa, 0.9%; South America, 0.5%) completed the survey in full. Management practices varied considerably. There was a clear preference for informal assessments, mainly oral-motor examinations, focusing on body functions and structures. The majority of respondents rejected the use of non-speech oral motor exercises as a clinical or carryover exercise. Variable satisfaction with current speech subsystem treatments was noted; however, overall, there was a general dissatisfaction. Whilst a strong interest in the use of NMES for dysarthria was evidenced, it was noted that most SLTs lacked fundamental knowledge of NMES principles and application. Conclusion SLTs’ management practices and satisfaction with acquired dysarthria treatments differed substantially. Investigations of the potential use of NMES for dysarthria treatment are of interest. WHAT THIS PAPER ADDS What is already known on the subject Recent country-specific surveys have explored speech-language therapists’ (SLTs’) assessment and intervention practices for acquired dysarthria. These studies indicate that although clinical management for this speech disorder mainly involves informal assessment tools and impairment-focused treatment, communication beyond the impairment, such as the activity and participation domains, is also frequently assessed and treated. What this paper adds to existing knowledge The majority of SLTs are dissatisfied with the overall benefits of current acquired dysarthria treatment. Phonatory, respiration and speech rate therapies are perceived to be more effective than prosody, articulation and resonance treatments. Despite a general lack of theoretical knowledge, most SLTs are interested in neuromuscular electrical stimulation treatment for acquired dysarthria. What are the potential or actual clinical implications of this work? New, evidence-based treatments are needed for SLTs to be confident in the effectiveness of their acquired dysarthria treatment

Understanding the diagnosis and management of multisystem inflammatory syndrome in adults (MIS-A) in the UK: results of a national Delphi process

Infection with SARS-CoV-2 may trigger a delayed hyper-inflammatory illness in children called paediatric multisystem inflammatory syndrome temporally associated with COVID-19 (PIMS-TS). A similar syndrome is increasingly recognised in adults termed multisystem inflammatory syndrome in adults (MIS-A) and may present acutely to medical or surgical specialties with severe symptoms, such as acute abdominal pain or cardiogenic shock. No national guidelines exist in the UK for the management of MIS-A and there is limited evidence to guide treatment plans. We undertook a national Delphi process to elicit opinions from experts in hyperinflammation about the diagnosis and management of MIS-A with the dual aim of improving recognition and producing a management guideline. Colleagues in paediatrics successfully initiated a national consensus management document that facilitated regional multidisciplinary referral and follow-up pathways for children with PIMS-TS, and we propose a similar system be developed for adult patients across the UK. This would facilitate better recognition and treatment of MIS-A across the multiple specialties to which it may present as well as enable follow-up with specialty services post-discharge