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Non-tuberculous mycobacterium encephalitis is rare. Since 2013, a global outbreak of Mycobacterium chimaera infection has been attributed to point-source contamination of heater cooler units used in cardiac surgery. Disseminated M. chimaera infection has presented many unique challenges, including non-specific clinical presentations with delays in diagnosis, and a high mortality rate among predominantly immunocompetent adults. Here, we describe three patients with fatal disseminated Mycobacterium chimaera infection showing initially non-specific, progressively worsening neurocognitive decline, including confusion, delirium, depression and apathy. Autopsy revealed widespread granulomatous encephalitis of the cerebrum, brain stem and spinal cord, along with granulomatous chorioretinitis. Cerebral involvement and differentiation between mycobacterial granulomas and microangiopathic changes can be assessed best on MRI with contrast enhancement. The prognosis of M. chimaera encephalitis appears to be very poor, but might be improved by increased awareness of this new syndrome and timely antimicrobial treatment.
This presentation will enable the learner to:
1.Describe the clinical, radiological and neuropathological findings of Mycobacterium chimaera encephalitis
2.Be aware of this rare form of encephalitis, and explain its diagnosis, prognosis and management
Uranium isotopes (238U/235U) have emerged as a proxy to reconstruct the redox conditions of the Earth's oceans and atmosphere based upon the large isotopic fractionation between reduced U(IV) and oxidized U(VI). Variations in 238U/235U, particularly when recorded in carbonate sediments, can track global trends in marine oxygenation and de-oxygenation. It is unique from other proxies because reduction primarily occurs at the sediment-water interface, and this sensitivity makes U isotopes especially relevant for the habitability of benthic animals. This Element covers the background, methods, and case studies of this promising tool for understanding Earth's environmental transitions, as rapid development continues to refine the accuracy of interpretations of 238U/235U records.
Background: Diffuse low-grade gliomas (LGGs) are primary brain tumours with infiltrative, anisotropic growth related to surrounding white and grey matter structures. Deformation-based morphometry (DBM) is a simple and objective image analysis method that can identify areas of local volume change over time. In this study, we illustrate the use of DBM to study the local expansion patterns of LGGs monitored by serial magnetic resonance imaging (MRI). Methods: We developed an image processing pipeline optimized for the study of LGG growth involving the fusion of follow-up MRIs for a given patient into an average template space using nonlinear registration. The displacement maps derived from nonlinear registration were converted to Jacobian maps, which estimate local tissue expansion and contraction over time. Results: Our results demonstrate that neoplastic growth occurs primarily around the edges of the tumour while the lesion core and areas adjacent to obstacles, such as the skull, show no significant expansion. Regions of normal brain tissue surrounding the lesion show slight contraction over time, representing compression due to mass effect of the tumour. Conclusions: DBM is a useful tool to understand the long-term clinical course of individual tumours and identify areas of rapid growth, which may explain the current presentation and/or predict future symptoms.
High-rate lithium ion batteries with long cycling lives can provide electricity grid stabilization services in the presence of large fractions of intermittent generators, such as photovoltaics. Engineering for high rate and long cycle life requires an appropriate selection of materials for both electrode and electrolyte and an understanding of how these materials degrade with use. High-rate lithium ion batteries can also facilitate faster charging of electric vehicles and provide higher energy density alternatives to supercapacitors in mass transport applications.
High-rate lithium ion batteries can play a critical role in decarbonizing our energy systems both through their underpinning of the transition to use renewable energy resources, such as photovoltaics, and electrification of transport. Their ability to be rapidly and frequently charged and discharged can enable this energy storage technology to play a key role in stabilizing future low-carbon electricity networks which integrate large fractions of intermittent renewable energy generators. This decarbonizing transition will require lithium ion technology to provide increased power and longer cycle lives at reduced cost. Rate performance and cycle life are ultimately limited by the materials used and the kinetics associated with the charge transfer reactions and ionic and electronic conduction. We review material strategies for electrode materials and electrolytes that can facilitate high rates and long cycle lives and discuss the important issues of cost, resource availability and recycling.
We investigate the interstellar medium towards seven TeV gamma-ray sources thought to be pulsar wind nebulae using Mopra molecular line observations at 7 mm [CS(1–0), SiO(1–0, v = 0)], Nanten CO(1–0) data and the Southern Galactic Plane Survey/GASS Hi survey. We have discovered several dense molecular clouds co-located to these TeV gamma-ray sources, which allows us to search for cosmic rays coming from progenitor SNRs or, potentially, from pulsar wind nebulae. We notably found SiO(1–0, v = 0) emission towards HESS J1809–193, highlighting possible interaction between the adjacent supernova remnant SNR G011.0–0.0 and the molecular cloud at d ∼ 3.7 kpc. Using morphological features, and comparative studies of our column densities with those obtained from X-ray measurements, we claim a distance d ∼ 8.6 − 9.7kpc for SNR G292.2–00.5, d ∼ 3.5 − 5.6 kpc for PSR J1418–6058 and d ∼ 1.5 kpc for the new SNR candidate found towards HESS J1303–631. From our mass and density estimates of selected molecular clouds, we discuss signatures of hadronic/leptonic components from pulsar wind nebulae and their progenitor SNRs. Interestingly, the molecular gas, which overlaps HESS J1026–582 at d ∼ 5 kpc, may support a hadronic origin. We find however that this scenario requires an undetected cosmic-ray accelerator to be located at d < 10 pc from the molecular cloud. For HESS J1809–193, the cosmic rays which have escaped SNR G011.0–0.0 could contribute to the TeV gamma-ray emission. Finally, from the hypothesis that at most 20% the pulsar spin down power could be converted into CRs, we find that among the studied pulsar wind nebulae, only those from PSR J1809–1917 could potentially contribute to the TeV emission.
Simulation-based training has a fundamental role in medical education as it allows the learner to gain experience managing emergencies in a safe, controlled environment.
This 1-day course consisted of eight high-fidelity simulation scenarios, followed by a video-assisted debrief focusing on the technical and non-technical (communication skills, teamwork, leadership and situational awareness) aspects of managing ENT and head and neck emergencies.
Eight courses have run since June 2014. Post-course questionnaires demonstrated that candidates’ confidence scores in managing airway and head and neck emergencies increased following completion of the course (p < 0.0001).
This was the first fully immersive ENT simulation course developed in the region. The learning objectives for each scenario were mapped to the ENT Intercollegiate Surgical Curriculum Programme. Feedback from the course indicated a continued demand for this style of training, leading to its inclusion in the training calendar.
We present observations of 50 deg2 of the Mopra carbon monoxide (CO) survey of the Southern Galactic Plane, covering Galactic longitudes l = 300–350° and latitudes |b| ⩽ 0.5°. These data have been taken at 0.6 arcmin spatial resolution and 0.1 km s−1spectral resolution, providing an unprecedented view of the molecular clouds and gas of the Southern Galactic Plane in the 109–115 GHz J = 1–0 transitions of 12CO, 13CO, C18O, and C17O.
We present a series of velocity-integrated maps, spectra, and position-velocity plots that illustrate Galactic arm structures and trace masses on the order of ~106 M⊙ deg−2, and include a preliminary catalogue of C18O clumps located between l = 330–340°. Together with the information about the noise statistics of the survey, these data can be retrieved from the Mopra CO website and the PASA data store.
Background: The hippocampus can be divided longitudinally into the head, body, and tail; and unfolded medial-to-laterally into the subiculum, cornu ammonis (CA) sectors, and the dentate gyrus. Ultra-high field (≥ 7 Tesla; 7T) magnetic resonance imaging (MRI) enables submillimetric visualization of these hippocampal substructures which could be valuable for surgical targeting. Here, we assess the feasibility of using 7T MRI in conjunction with a novel computational unfolding method for image-based stereotactic targeting of hippocampal substructures. Methods: 53 patients with drug-resistant epilepsy were identified undergoing first-time implantation of the hippocampus. An image processing pipeline was created for computationally transforming post-operative electrode contact locations into our hippocampal coordinate system. Results: Of 178 implanted hippocampal electrodes (88 left; 49.4%), 25 (14.0%) were predominantly in the subiculum, 85 (47.8%) were in CA1, 23 (12.9%) were in CA2, 18 (10.1%) were in CA3/CA4, and 27 (15.2%) were in dentate gyrus. Along the longitudinal axis, hippocampal electrodes were most commonly implanted in the body (92; 51.7%) followed by the head (86; 48.3%). Conclusions: 7T MRI enables high-resolution anatomical imaging on the submillimeter scale in in vivo subjects. Here, we demonstrate the utility of 7T imaging for identifying the relative location of SEEG electrode implantations within hippocampal substructures for the invasive investigation of epilepsy.
Mechanical Turk has become an important source of subjects for social science experiments, providing a low-cost alternative to the convenience of using undergraduates while avoiding the expense of drawing fully representative samples. However, we know little about how the rates we pay to “Turkers” for participating in social science experiments affects their participation. This study examines subject performance using two experiments – a short survey experiment and a longer dynamic process tracing study of political campaigns – that recruited Turkers at different rates of pay. Looking at demographics and using measures of attention, engagement and evaluation of the candidates, we find no effects of pay rates upon subject recruitment or participation. We conclude by discussing implications and ethical standards of pay.
Intranasal splints have long been utilised as a post-operative adjunct in septoplasty, intended to reduce the risk of adhesions and haematoma formation, and to maintain alignment during healing.
A Medline literature review of the history and evolution of intranasal splint materials and designs was performed. Advantages and disadvantages of various splints are discussed.
Intranasal splints fashioned from X-ray film were first reported in 1955. Since then, a variety of materials have been utilised, including polyethylene coffee cup lids, samarium cobalt magnets and dental utility wax. Most contemporary splints are produced from silicon rubber or polytetrafluoroethylene (Teflon). Designs have varied in thickness, flexibility, shape, absorption and the inclusion of built-in airway tubes. Future directions in splint materials and designs are discussed.
Intranasal splints have steadily evolved since 1955, with numerous novel innovations. Despite their simplicity, they play an important role in nasal surgery and will continue to evolve over time.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
HESS J1614–518 and HESS J1616–508 are two tera-electron volt γ-ray sources that are not firmly associated with any known counterparts at other wavelengths. We investigate the distribution of interstellar medium towards the tera-electron volt γ-ray sources using results from a 7-mm-wavelength Mopra study, the Mopra Southern Galactic Plane CO Survey, the Millimetre Astronomer’s Legacy Team-45 GHz survey and [C i] data from the HEAT telescope. Data in the CO(1–0) transition lines reveal diffuse gas overlapping the two tera-electron volt sources at several velocities along the line of sight, while observations in the CS(1–0) transition line reveal several interesting dense gas features. To account for the diffuse atomic gas, archival H i data was taken from the Southern Galactic Plane Survey. The observations reveal gas components with masses ~103 to 105 M⊙ and with densities ~102 to 103 cm−3 overlapping the two tera-electron volt sources. Several origin scenarios potentially associated with the tera-electron volt γ-ray sources are discussed in light of the distribution of the local interstellar medium. We find no strong convincing evidence linking any counterpart with HESS J1614–518 or HESS J1616–508.
We present a re-analysis of the results obtained from a series of measurements on freshwater and saline ice beams under various centrifugal accelerations. The data show a strong influence of beam size, brine volume and centrifugal acceleration on the elastic modulus of ice. The data suggest a transition brine volume at around 9%, which might occur close to the melting point, at which the elastic modulus of ice drops rapidly due to a possible change of brine-pocket structure. Furthermore, for brine volumes less than 9%, there is a negligible increase in the elastic modulus measured under high centrifugal acceleration, but for brine volumes more than 9% the increase is considerable, approaching that measured with freshwater ice. This may be due to necking of brine drainage channels just above the ice/water interface at high centrifugal acceleration. A model of sea ice was constructed based on existing theories of brine inclusions in sea ice, which satisfactorily predicts the observed trends.
Background: The goal of a brain tumour operation is maximal safe resection. No widely used guidelines for the use of functional magnetic resonance imaging (fMRI) in these patients currently exist. In this study we are trying to determine if and how Canadian neurosurgeons use fMRI in the management of patients with low grade glioma (LGG). Methods: A 15-25 minute survey was created using an online survey tool. In Part One of the study the survey was distributed to neurosurgery consultant and resident staff at the London Health Sciences Centre (LHSC). In Part Two of the study the survey is being distributed to members of the Canadian Neurosurgical Society. The survey consists of two sections - background and case-based decision making. Results: There were six surveys from the LHSC staff. On average respondents indicated that they obtain fMRI for 9% of LGG patients, though 67% indicated that they were comfortable ordering and interpreting fMRI studies. In the case-based section, fMRI data did not tend to affect respondents’ preferred treatment, confidence in their treatment, or their predicted risk of surgical treatment. Conclusions: In this limited survey of LHSC neurosurgical staff there was no regular use of fMRI in LGG patients. We await the results of a national survey of Canadian neurosurgeons.
A current trend in the aeronautic industry is to increase the wing aspect ratio to enhance aerodynamic efficiency by reducing the induced drag and thus reduce fuel consumption. Despite the associated benefits of a large aspect ratio, such as higher lift-to-drag ratios and range, commercial aircraft usually have a relatively low aspect ratio. This is partially explained by the fact that the wing becomes more flexible with increasing aspect ratio and thus more prone to large deflections, which can cause aeroelastic instability problems such as flutter. In this work, an aeroelastic study is conducted on a rectangular wing model of 20 m span and variable chord for a low subsonic speed condition to evaluate the differences between linear and non-linear static aeroelastic responses. Comparisons between linear and non-linear displacements, natural frequencies and flutter boundary are performed. An in-house non-linear aeroelastic framework was employed for this purpose. In this work, the influence of the aspect ratio and geometric non-linearity (highly deformed states) is assessed in terms of aeroelastic performance parameters: flutter speed and divergence speed. A nearly linear correlation of flutter speed difference (relative to linear analysis results) with vertical-tip displacement difference is observed. The flutter and divergence speeds vary substantially as the wing aspect ratio increases, and the divergence speeds always remain above the flutter speed. Furthermore, the flutter mechanism was observed to change as the wing chord is decreased.
The development of an economic capital model requires a decision to be made regarding how to aggregate capital requirements for the individual risk factors while taking into account the effects of diversification. Under the Individual Capital Adequacy Standards framework, UK life insurers have commonly adopted a correlation matrix approach due to its simplicity and ease in communication to the stakeholders involved, adjusting the result, where appropriate, to allow for non-linear interactions. The regulatory requirements of Solvency II have been one of the principal drivers leading to an increased use of more sophisticated aggregation techniques in economic capital models. This paper focusses on a simulation-based approach to the aggregation of capital requirements using copulas and proxy models. It describes the practical challenges in parameterising a copula including how allowance may be made for tail dependence. It also covers the challenges associated with fitting and validating a proxy model. In particular, the paper outlines how insurers could test, communicate and justify the choices made through the use of some examples.
The present study addresses the reaction zone structure and burning mechanism of unstable detonations. Experiments investigated mainly two-dimensional methane–oxygen cellular detonations in a thin channel geometry. The sufficiently high temporal resolution permitted the determination of the probability density function of the shock distribution, a power law with an exponent of
, and the burning rate of unreacted pockets from their edges – through surface turbulent flames with a speed approximately 3–7 times larger than the laminar one at the local conditions. Numerical simulations were performed using a novel large-eddy simulation method where the reactions due to both autoignition and turbulent transport were treated exactly at the subgrid scale in a reaction–diffusion formulation. The model is an extension of Kerstein and Menon’s linear eddy model for large-eddy simulation to treat flows with shock waves and rapid gas-dynamic transients. The two-dimensional simulations recovered well the amplification of the laminar flame speed due to the turbulence generated mainly by the shear layers originating from the triple points and subsequent Richtmyer–Meshkov instability associated with the internal pressure waves. The simulations clarified how the level of turbulence generated controlled the burning rate of the pockets, the hydrodynamic thickness of the wave, the cellular structure and its distribution. Three-dimensional simulations were found to be in general good agreement with the two-dimensional ones, in that the subgrid-scale model captured the ensuing turbulent burning once the scales associated with the cellular dynamics, where turbulent kinetic energy is injected, are well resolved.
To identify the common causal beliefs of mental illness in a multi-ethnic Southeast Asian community and describe the sociodemographic associations to said beliefs. The factor structure to the causal beliefs scale is explored. The causal beliefs relating to five different mental illnesses (alcohol abuse, depression, obsessive-compulsive disorder (OCD), dementia and schizophrenia) and desire for social distance are also investigated.
Data from 3006 participants from a nationwide vignette-based study on mental health literacy were analysed using factor analysis and multiple logistic regression to address the aims. Participants answered questions related to sociodemographic information, causal beliefs of mental illness and their desire for social distance towards those with mental illness.
Physical causes, psychosocial causes and personality causes were endorsed by the sample. Sociodemographic differences including ethnic, gender and age differences in causal beliefs were found in the sample. Differences in causal beliefs were shown across different mental illness vignettes though psychosocial causes was the most highly attributed cause across vignettes (endorsed by 97.9% of respondents), followed by personality causes (83.5%) and last, physical causes (37%). Physical causes were more likely to be endorsed for OCD, depression and schizophrenia. Psychosocial causes were less often endorsed for OCD. Personality causes were less endorsed for dementia but more associated with depression.
The factor structure of the causal beliefs scale is not entirely the same as that found in previous research. Further research on the causal beliefs endorsed by Southeast Asian communities should be conducted to investigate other potential causes such as biogenetic factors and spiritual/supernatural causes. Mental health awareness campaigns should address causes of mental illness as a topic. Lay beliefs in the different causes must be acknowledged and it would be beneficial for the public to be informed of the causes of some of the most common mental illnesses in order to encourage help-seeking and treatment compliance.
Pertussis epidemics have displayed substantial spatial heterogeneity in countries with high socioeconomic conditions and high vaccine coverage. This study aims to investigate the relationship between pertussis risk and socio-environmental factors on the spatio-temporal variation underlying pertussis infection. We obtained daily case numbers of pertussis notifications from Queensland Health, Australia by postal area, for the period January 2006 to December 2012. A Bayesian spatio-temporal model was used to quantify the relationship between monthly pertussis incidence and socio-environmental factors. The socio-environmental factors included monthly mean minimum temperature (MIT), monthly mean vapour pressure (VAP), Queensland school calendar pattern (SCP), and socioeconomic index for area (SEIFA). An increase in pertussis incidence was observed from 2006 to 2010 and a slight decrease from 2011 to 2012. Spatial analyses showed pertussis incidence across Queensland postal area to be low and more spatially homogeneous during 2006–2008; incidence was higher and more spatially heterogeneous after 2009. The results also showed that the average decrease in monthly pertussis incidence was 3·1% [95% credible interval (CrI) 1·3–4·8] for each 1 °C increase in monthly MIT, while average increase in monthly pertussis incidences were 6·2% (95% CrI 0·4–12·4) and 2% (95% CrI 1–3) for SCP periods and for each 10-unit increase in SEIFA, respectively. This study demonstrated that pertussis transmission is significantly associated with MIT, SEIFA, and SCP. Mapping derived from this work highlights the potential for future investigation and areas for focusing future control strategies.