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This report describes a cluster of patients infected by Serratia marcescens in a metropolitan neonatal intensive care unit (NICU) and a package of infection control interventions that enabled rapid, effective termination of the outbreak.
Cross-sectional analytical study using whole-genome sequencing (WGS) for phylogenetic cluster analysis and identification of virulence and resistance genes.
NICU in a metropolitan tertiary-care hospital in Sydney, Australia.
All neonates admitted to the level 2 and level 3 neonatal unit.
Active inpatient and environmental screening for Serratia marcescens isolates with WGS analysis for identification of resistance genes as well as cluster relatedness between isolates. Planning and implementation of a targeted, multifaceted infection control intervention.
The cluster of 10 neonates colonized or infected with Serratia marcescens was identified in a metropolitan NICU. Two initial cases involved devastating intracranial infections with brain abscesses, highlighting the virulence of this organism. A targeted and comprehensive infection control intervention guided by WGS findings enabled termination of this outbreak within 15 days of onset. WGS examination demonstrated phylogenetic linkage across the cluster, and genomic unrelatedness of later strains identified in the neonatal unit and elsewhere.
A comprehensive, multipronged, infection control package incorporating close stakeholder engagement, frequent microbiological patient screening, environmental screening, enhanced cleaning, optimization of hand hygiene and healthcare worker education was paramount to the prompt control of Serratia marcescens transmission in this neonatal outbreak. WGS was instrumental in establishing relatedness between isolates and identification of possible transmission pathways in an outbreak setting.
To design a meditation protocol and test its feasibility, acceptability and efficacy in conjunction with yoga training (YT) for persons with schizophrenia (SZ).
The meditation protocol consisted of Anapana (observing normal respiration) and Yoga Nidra (supine, restful awareness). In a single-blind randomised controlled trial, medicated and clinically stable outpatients diagnosed with SZ were randomised to receive treatment as usual (TAU), TAU augmented with YT or TAU augmented with meditation and yoga training (MYT) for 3 weeks (N = 145). Acceptability, clinical, social and cognitive functions were assessed after 3-week and 3-month post-randomisation using within-group and between-group analyses with repeated measures multivariate tests.
No group-wise differences in compliance, study discontinuation, major/serious side effects or adverse events were noted. For six assessed clinical variables, the direction of changes were in the desired direction and the effect sizes were greater in the MYT group compared with the TAU group at both time points. Changes in social function variables were greater at 3 months than at 3 weeks. Nominally significant improvement in individual cognitive domains were noted in all groups at both time points. All effect sizes were in the small to medium range.
MYT is feasible and acceptable and shows modest benefits for persons with SZ. MYT can also improve quality of life and clinical symptoms. Larger studies of longer duration are warranted.
As part of a project to implement antimicrobial dashboards at select facilities, we assessed physician attitudes and knowledge regarding antibiotic prescribing.
An online survey explored attitudes toward antimicrobial use and assessed respondents’ management of four clinical scenarios: cellulitis, community-acquired pneumonia, non–catheter-associated asymptomatic bacteriuria, and catheter-associated asymptomatic bacteriuria.
This study was conducted across 16 Veterans’ Affairs (VA) medical centers in 2017.
Physicians working in inpatient settings specializing in infectious diseases (ID), hospital medicine, and non-ID/hospitalist internal medicine.
Scenario responses were scored by assigning +1 for answers most consistent with guidelines, 0 for less guideline-concordant but acceptable answers and −1 for guideline-discordant answers. Scores were normalized to 100% guideline concordant to 100% guideline discordant across all questions within a scenario, and mean scores were calculated across respondents by specialty. Differences in mean score per scenario were tested using analysis of variance (ANOVA).
Overall, 139 physicians completed the survey (19 ID physicians, 62 hospitalists, and 58 other internists). Attitudes were similar across the 3 groups. We detected a significant difference in cellulitis scenario scores (concordance: ID physicians, 76%; hospitalists, 58%; other internists, 52%; P = .0087). Scores were numerically but not significantly different across groups for community-acquired pneumonia (concordance: ID physicians, 75%; hospitalists, 60%; other internists, 56%; P = .0914), for non–catheter-associated asymptomatic bacteriuria (concordance: ID physicians, 65%; hospitalists, 55%; other internists, 40%; P = .322), and for catheter-associated asymptomatic bacteriuria (concordance: ID physicians, 27% concordant; hospitalists, 8% discordant; other internists 13% discordant; P = .12).
Significant differences in performance regarding management of cellulitis and low overall performance regarding asymptomatic bacteriuria point to these conditions as being potentially high-yield targets for stewardship interventions.
In this chapter the principles of composite manufacture are discussed. The advantages and disadvantages of each method are considered in identifying a process for a particular artefact. Specifically, the need to use sophisticated fibre placement techniques in manufacture is described.
In this chapter we describe the resins used for the manufacture of composite artefacts. The concept of curing is discussed with respect to the chemistry of typical polymer matrices. The advantages and disadvantages of thermosets and thermoplastics are also discussed.
In the case of thermosets, the importance of thermoplastic and rubber toughening is considered. While we concentrate on polymer matrix materials, ceramic and metal matrices are referred to for completeness.
Fibrous reinforcement of materials has been employed over many centuries to increase performance. Many early plastics materials of the late nineteenth and early twentieth centuries relied on ‘fibrous’ inclusions, while the development of glass fibres for polymer reinforcement in the 1930s introduced the material known as fibreglass. Eventually, with the development of boron fibres for metal reinforcement and the discovery of high-strength carbon fibres in 1964, the term composites came into general use. More recently, carbon nanotubes and related materials and graphene have led to the development of nano-composites. The Composites Age has arrived.
This chapter describes the synthesis of the principal fibres and provides the range of acicular reinforcing particles, nanofibres, nanotubes, and nanosheets. The properties of the most common fibres – carbon, glass, ceramics, and natural and advanced polymers – are considered. The differing grades and their structural property relationships are also discussed. Surface treatments for adhesion and compatibility are described.
Polymeric matrices absorb moisture, so here we examine how this affects the performance of a composite material. For an aerospace artefact, absorption and desorption is an important issue. For example, on the tarmac the relative humidity (RH) is high, whereas in flight the RH is low. Also, the ambient temperature can vary significantly, whereas the skin of a military aircraft may reach temperatures of 120 °C in flight. Therefore, we consider the effects of RH, temperature, and thermal excursions on moisture absorption and how they influence the micromechanics. Initially we can assume that the fibres are insensitive to water, which is realistic for most common reinforcements apart from aramid fibres.
Protocols for repair and recycling of composites are described. Future developments that embrace self-healing systems are also considered. End-of-life options such as fibre and matrix recovery are also discussed. The economics of differing approaches are briefly considered using a whole-life cost model.
In this chapter the micromechanics of unidirectional fibre composites (see Section 5.1) are extended to laminates, where strain transfer occurs at a matrix crack other than at a fibre-break. The stress distribution under load is also discussed to describe the accumulation of damage under differing loading conditions.
Since the discovery of carbon fibres in the 1960s, the applications have grown. Because of the high specific strength and stiffness, aerospace applications have dominated, especially initially in military aircraft. The intent here is to demonstrate how the choice of material has been identified. Most critical demonstrators have come from the field of aerospace because of the benefits of carbon fibres and the development of confidence in their use in safety-critical designs. The latter has involved much testing and durability studies. Middleton has provided several case histories detailing the development of composite applications in aircraft structures . The use of composite components has increased with improved confidence in the durability and reliability of these materials and structures. The Airbus A380 was introduced in 2006 using a carbon-fibre-reinforced polymer (CFRP) centre wing box, while the fuselage employed an aluminium–glass fibre composite laminate (GLARE). The centre wing box is a critical carbon-fibre composite structure that joins the wings to the fuselage. Together with several other composite components, such as the horizontal and vertical stabilizers, keel beam, and pressure bulkhead, the total composite usage is 22% w/w. In 2011 the Boeing 787 Dreamliner employed carbon-fibre materials for the fuselage and wings. In total, the latter used 80–90% by volume or 50% by weight of composite materials. The Airbus A350, introduced in 2015, also uses CFRP for the fuselage and wings, and in total composite usage is 53% w/w.
This chapter describes the mechanical performance of a fibre composite. A number of variables that control deformation and fracture are discussed: continuous or discontinuous fibres; fibre angle; fibre length; the transfer of stress between matrix and fibre at a short fibre and/or a fibre-break; and the role of the matrix. Individual components can fracture independently and control the micromechanics; the redistribution of stress after these events is discussed.
Understand critical principles of composites, such as design of durable structures, choice of fibre, matrix, manufacturing process, and mechanics with this interdisciplinary text. The book features up-to-date coverage of hybrids of fibres and particles and explanation of failure criteria, and includes a comprehensive discussion on choice of fibres, matrices, manufacturing technology, and micromechanics for durable composite structures. It provides the structure and properties of reinforcing fibres, particulates, and matrices together with a discussion of fracture mechanics. This is an essential guide for scientists and engineers wishing to discover the benefits of composite materials for designing strong and durable structures.
A comparison of computer-extracted and facility-reported counts of hospitalized coronavirus disease 2019 (COVID-19) patients for public health reporting at 36 hospitals revealed 42% of days with matching counts between the data sources. Miscategorization of suspect cases was a primary driver of discordance. Clear reporting definitions and data validation facilitate emerging disease surveillance.