Recommended operating room practice during the COVID-19 pandemic: systematic review

Background The COVID-19 pandemic poses a critical global public health crisis. Operating room (OR) best practice in this crisis is poorly defined. This systematic review was performed to identify contemporary evidence relating to OR practice in the context of COVID-19. Methods MEDLINE was searched systematically using PubMed (search date 19 March 2020) for relevant studies in accordance with PRISMA guidelines. Documented practices and guidance were assessed to determine Oxford Centre for Evidence-Based Medicine (OCEBM) levels of evidence, and recommendations for practice within five domains were extracted: physical OR, personnel, patient, procedure, and other factors. Results Thirty-five articles were identified, of which 11 met eligibility criteria. Nine articles constituted expert opinion and two were retrospective studies. All articles originated from the Far East (China, 9; Singapore, 2); eight of the articles concerned general surgery. Common themes were identified within each domain, but all recommendations were based on low levels of evidence (median OCEBM level 5 (range 4–5)). The highest number of overlapping recommendations related to physical OR (8 articles) and procedural factors (13). Although few recommendations related to personnel factors, consensus was high in this domain, with all studies mandating the use of personal protective equipment. Conclusion There was little evidence to inform this systematic review, but there was consensus regarding many aspects of OR practice. Within the context of a rapidly evolving pandemic, timely amalgamation of global practice and experiences is needed to inform best practice

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Teaching readings?

[Extract] Coming to terms with many of the recent changes in thinking about reading texts is difficult. Most teachers in the western world have trained in a quite different tradition, and the question,” What does it mean in the classroom?” is not addressed explicitly by most recent theory. The idea, for example, that a text might be thought of as a site for the production of multiple—and often contradictory or competing—meanings is a particularly challenging one in the context of the classroom. Moving from a conception of the text as a container of correct meanings for which readers must search, to one in which meanings are thought about as produced rather than discovered, and contested rather than agreed, has enormous implications in terms of assessment and power. Which meanings, after all, are to prevail? Being able to ask questions about the meanings produced of texts seems to offer productive possibilities for practice because recent literary theory appears to suggest that through their taking up of multiple reading positions, readers might be able to reflect on the readings that they and others produce. So that by encouraging students to read in a way that involved the construction of multiple readings of a text, we thought the likelihood of constructing readers who were critically conscious and aware appeared to be increased. There are, of course, several competing strands to recent theory as it is propounded in the Australian context, whether applied to literary texts or popular culture, but initially, we took from it four principles: that a starting point for a discussion about texts is that they are made; that texts do not emerge from a timeless, placeless zone but are written and read in particular social contexts; that texts are sites for the production of meanings that may have nothing to do with what the writer intended; and that texts are sites for the production of multiple and frequently contradictory meanings

The effect of silicon content on long crack fatigue behaviour of aluminium-silicon piston alloy at elevated temperatures

The microstructure of aluminium piston alloys comprises primary and eutectic silicon together with numerous intermetallics. Previous research has shown that primary silicon strongly influences both fatigue crack initiation and subsequent propagation behaviour, however, the detailed effects of varying silicon volume fraction and morphology have not been fully addressed. Therefore, the fatigue properties of a number of candidate piston alloys with varying volume fractions of silicon have been studied. Long crack fatigue tests have been performed at room and elevated temperature typical of the gudgeon pin boss (200 8C) using a test frequency of 15 Hz (a typical engine frequency at engine idle condition). Microstructural characterisation using image analysis approaches combined with optical profilometry has been used to assess the fracture surfaces of test samples. The role of primary Si in enhancing crack growth rates at high DK levels, whilst affording improvements in crack growth rates at lower DK levels due to local crack deflections and shielding, has been confirmed. In the absence of primary Si (lower Si content alloys) the low DK level crack growth behaviour is dominated by matrix properties (intra-dendritic crack growth pre-dominates) whilst the high DK level crack growth behaviour is inter-dendritic and occurs along the weak path of the eutectic Si and/or intermetallic network

Resting and exercising cardiorespiratory variables and acute mountain sickness

The incidence of AMS in our study was low reflecting a conservative ascent profile. Further larger studies are necessary to fully assess the predictive value of cardiorespiratory variables in AMS

The mechanisms of long fatigue crack growth behaviour in Al–Si casting alloys at room and elevated temperature

Pistons are commonly made from multicomponent Al–Si casting alloys, which have complex, interconnecting three-dimensional (3D) networks of secondary phase particles. They are non-serviceable parts and so must be able to withstand high cycle fatigue while operating at temperatures between 30 and 80% of Tm. Long fatigue crack growth tests were performed at room temperature (RT) and 350uC to assess the micromechanisms of fatigue. The fracture profiles at low and high da/dN were analysed; at low crack growth rates at both temperatures there is no crack path preferentiality with respect to the microstructure. At high da/dN in the RT sample the crack growth occurs preferentially via hard particles, while at 350uC there is a change in mechanism and the crack appears to avoid hard particles. X-ray tomography has been used to image the crack tips and gain a detailed insight into the mechanisms of fatigue in these complex 3D microstructures

Factors mediating the routinisation of e-learning within a traditional university education environment

Technology-enhanced or Computer Aided Learning (e-learning) can be institutionally integrated and supported by learning management systems or Virtual Learning Environments (VLEs) to offer efficiency gains, effectiveness and scalability of the e-leaning paradigm. However this can only be achieved through integration of pedagogically intelligent approaches and lesson preparation tools environment and VLE that is well accepted by both the students and teachers. This paper critically explores some of the issues relevant to scalable routinisation of e-learning at the tertiary level, typically first year university undergraduates, with the teaching of Relational Data Analysis (RDA), as supported by multimedia authoring, as a case study. The paper concludes that blended learning approaches which balance the deployment of e-learning with other modalities of learning delivery such as instructor–mediated group learning etc offer the most flexible and scalable route to e-learning but that this requires the graceful integration of platforms for multimedia production, distribution and delivery through advanced interactive spaces that provoke learner engagement and promote learning autonomy and group learning facilitated by a cooperative-creative learning environment that remains open to personal exploration of constructivist-constructionist pathways to learning

Microstructural analysis of fatigue initiation in Al-Si casting alloys

Fatigue initiation behaviour in three multi-component Al-Si casting alloys with varying Si content is compared using a range of microscopy and analytical techniques. A higher proportion of stiffer secondary phases leads to load transfer effects reducing particle cracking and particle/matrix debonding. Si appears stronger than the Al9FeNi phase, which cracks and debonds to form initiation sites preferentially over Si. Reducing Si content results in clusters of intermetallics forming, and increased porosity. The effect of porosity, combined with mesoscopic load transfer effects to the high volume fraction intermetallic regions make these potent crack initiation sites in low silicon alloys