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Comparing the feasibility of ovine and synthetic temporal bones for simulating endoscopic ear surgery against the ‘gold standard’ of human cadaveric tissue.
A total of 10 candidates (5 trainees and 5 experts) performed endoscopic tympanoplasty on 3 models: Pettigrew temporal bones, ovine temporal bones and cadaveric temporal bones. Candidates completed a questionnaire assessing the face validity, global content validity and task-specific content validity of each model.
Regarding ovine temporal bone validity, the median values were 4 (interquartile range = 4–4) for face validity, 4 (interquartile range = 4–4) for global content validity and 4 (interquartile range = 4–4) for task-specific content validity. For the Pettigrew temporal bone, the median values were 3.5 (interquartile range = 2.25–4) for face validity, 3 (interquartile range = 2.75–3) for global content validity and 3 (interquartile range = 2.5–3) for task-specific content validity. The ovine temporal bone was considered significantly superior to the Pettigrew temporal bone for the majority of validity categories assessed.
Tympanoplasty is feasible in both the ovine temporal bone and the Pettigrew temporal bone. However, the ovine model was a significantly more realistic simulation tool.
Currently no national guidelines exist for the management of scabies outbreaks in residential or nursing care homes for the elderly in the United Kingdom. In this setting, diagnosis and treatment of scabies outbreaks is often delayed and optimal drug treatment, environmental control measures and even outcome measures are unclear. We undertook a systematic review to establish the efficacy of outbreak management interventions and determine evidence-based recommendations. Four electronic databases were searched for relevant studies, which were assessed using a quality assessment tool drawing on STROBE guidelines to describe the quality of observational data. Nineteen outbreak reports were identified, describing both drug treatment and environmental management measures. The quality of data was poor; none reported all outcome measures and only four described symptom relief measures. We were unable to make definitive evidence-based recommendations. We draw on the results to propose a framework for data collection in future observational studies of scabies outbreaks. While high-quality randomised controlled trials are needed to determine optimal drug treatment, evidence on environmental measures will need augmentation through other literature studies. The quality assessment tool designed is a useful resource for reporting of outcome measures including patient-reported measures in future outbreaks.
Eigenmodes of averaged small-amplitude perturbations to a turbulent channel flow – which is one of the most fundamental canonical flows – are identified for the first time via an extensive set of high-fidelity graphics processing unit accelerated direct numerical simulations. While the system governing averaged small-amplitude perturbations to turbulent channel flow remains unknown, the fact such eigenmodes can be identified constitutes direct evidence that it is linear. Moreover, while the eigenvalue associated with the slowest-decaying anti-symmetric eigenmode mode is found to be real, the eigenvalue associated with the slowest-decaying symmetric eigenmode mode is found to be complex. This indicates that the unknown linear system governing the evolution of averaged small-amplitude perturbations cannot be self-adjoint, even for the case of a uni-directional flow. In addition to elucidating aspects of the flow physics, the findings provide guidance for development of new unsteady Reynolds-averaged Navier–Stokes turbulence models, and constitute a new and accessible benchmark problem for assessing the performance of existing models, which are used widely throughout industry.
At GE Research, we are combining “physics” with artificial intelligence and machine learning to advance manufacturing design, processing, and inspection, turning innovative technologies into real products and solutions across our industrial portfolio. This article provides a snapshot of how this physical plus digital transformation is evolving at GE.
Simulated heat-affected zones (HAZs) were made in austenitic sta.inless steel specimens using a Gleeble. The samples were heated to temperatures as high as 1100°C by computer controlled resistance heating. By controlling the heating rate, maximum temperature, and cooling rate, a wide range of residual stresses were introduced in the specimens. Stress measurements were made using X-ray diffraction. It was found that significant stress gradients were produced in the simulated HAZs, and that all stresses were compressive in nature, both in the longitudinal and transverse directions. These results are not representative of the residual stresses determined in the HAZs of real welds, thus calling into question some aspects of the role of the Gleeble in such simulations.
Elderly patients have been consistently shown to receive suboptimal therapy for cancers of the head and neck. This study was performed to determine the peri-operative outcomes of these patients and compare them with those of younger patients.
In this retrospective analysis, 115 patients aged 70 years or more undergoing major surgery for head and neck cancers were matched with 115 patients aged 50–60 years, and univariate analysis was performed.
Elderly patients had a reduced performance status (p < 0.001) and more co-morbid illnesses (p = 0.007), but a comparable intra-operative course. They had a longer median hospital stay (p = 0.016), longer intensive care unit stay (p = 0.04), longer median tracheostomy dependence (p = 0.04) and were more often discharged with feeding tubes (p < 0.001). They also had a higher incidence of post-operative non-fatal cardiac events (p = 0.045).
Elderly patients with good performance status should receive curative-intent surgery. Although hospital stay and tube dependence are longer, morbidity and mortality are comparable with younger patients.
Metal–graphene composites are sought after for various applications. A hybrid light-weight foam of nickel (Ni) and reduced graphene oxide (rGO), called Ni-rGO, is reported here for small molecule oxidations and thereby their sensing. Methanol oxidation and non-enzymatic glucose sensing are attempted with the Ni-rGO foam via electrocatalytically, and an enhanced methanol oxidation current density of 4.81 mA/cm2 is achieved, which is ~1.7 times higher than that of bare Ni foam. In glucose oxidation, the Ni-rGO electrode shows a better sensitivity over bare Ni foam electrode where it could detect glucose linearly over a concentration range of 10 µM to 4.5 mM with a very low detection limit of 3.6 µM. This work demonstrates the synergistic effects of metal and graphene in oxidative processes, and also shows the feasibility of scalable metal–graphene composite inks development for small molecule printable sensors and fuel cell catalysts.
In many parts of the world, mostly low- and middle-income countries, timely diagnosis and repair of congenital heart diseases (CHDs) is not feasible for a variety of reasons. In these regions, economic growth has enabled the development of cardiac units that manage patients with CHD presenting later than would be ideal, often after the window for early stabilisation – transposition of the great arteries, coarctation of the aorta – or for lower-risk surgery in infancy – left-to-right shunts or cyanotic conditions. As a result, patients may have suffered organ dysfunction, manifest signs of pulmonary vascular disease, or the sequelae of profound cyanosis and polycythaemia. Late presentation poses unique clinical and ethical challenges in decision making regarding operability or surgical candidacy, surgical strategy, and perioperative intensive care management.
Commonly thought of as a disease of poverty and overcrowding in resource-poor settings globally, scabies is also an important public health issue in residential care facilities for the elderly (RCFE) in high-income countries such as the UK. We compared and contrasted current local Health Protection Team (HPT) guidelines for the management of scabies outbreaks in RCFE throughout England. We performed content analysis on 20 guidelines, and used this to create a quantitative report of their variation in key dimensions. Although the guidelines were generally consistent on issues such as the treatment protocols for individual patients, there was substantial variation in their recommendations regarding the prophylactic treatment of contacts, infection control measures and the roles and responsibilities of individual stakeholders. Most guidelines did not adequately address the logistical challenges associated with mass treatment in this setting. We conclude that the heterogeneous nature of the guidelines reviewed is an argument in favour of national guidelines being produced.
Quasi-one-dimensional (quasi-1D) tools developed for capturing flow and acoustic dynamics in non-segmented solid rocket motors are evaluated using multi-dimensional computational fluid dynamic simulations and used to characterise damping of modal perturbations. For motors with high length-to-diameter ratios (of the order of 10), remarkably accurate estimates of frequencies and damping rates of lower modes can be obtained using the the quasi-1D approximation. Various grain configurations are considered to study the effect of internal geometry on damping rates. Analysis shows that lower cross-sectional area at the nozzle entry plane is found to increase damping rates of all the modes. The flow-turning loss for a mode increases if the more mass addition due to combustion is added at pressure nodes. For the fundamental mode, this loss is, therefore, maximum if burning area is maximum at the centre. The insights from this study in addition to recommendations made by Blomshield(1) based on combustion considerations would be very helpful in realizing rocket motors free from combustion instability.
In our previous works (Anosova 1987, Anosova, Iyer, Varma 1994), we developed a new method for determination of the structure of a clustered distribution. In this work, we apply this method studying the observed distribution of galaxies in the Universe.
The Fontan connection, originally described in 1971, is used to provide palliation for patients with many forms of CHDs that cannot support a biventricular circulation. An increasing number of females who have undergone these connections in childhood are now surviving into adulthood and some are becoming pregnant. We report a case of a 29-year-old woman who presented with a twin pregnancy at 33 weeks of gestation. She had significant deterioration of her cardiovascular status before the twin babies were delivered by emergency caesarean section owing to associated obstetric complications. This report also highlights the various maternal and fetal complications occurring in pregnancy of Fontan-palliated patients and suggests the need for meticulous pre-conception counselling and strict perinatal care.
In this study, we present the case of a neonate with obstructed infracardiac total anomalous pulmonary venous connection with severe pulmonary hypertension and a patent ductus arteriosus with right-to-left shunting. The patient had an unusual finding of pandiastolic flow reversal in the upper descending thoracic aorta. He underwent emergency surgical re-routing of the pulmonary veins to the left atrium, and postoperative echocardiography showed disappearance of the descending aortic flow reversal. We hypothesise that in severely obstructed total anomalous pulmonary venous connection the left ventricular output may be extremely low, resulting in flow reversal in the descending aorta.
Direct numerical simulation (DNS) and dynamic mode decomposition (DMD) are used to study the shear layer characteristics of a jet in a crossflow. Experimental observations by Megerian et al. (J. Fluid Mech., vol. 593, 2007, pp. 93–129) at velocity ratios (
) of 2 and 4 and Reynolds number (
) of 2000 on the transition from absolute to convective instability of the upstream shear layer are reproduced. Point velocity spectra at different points along the shear layer show excellent agreement with experiments. The same frequency (
) is dominant along the length of the shear layer for
, whereas the dominant frequencies change along the shear layer for
. DMD of the full three-dimensional flow field is able to reproduce the dominant frequencies observed from DNS and shows that the shear layer modes are dominant for both the conditions simulated. The spatial modes obtained from DMD are used to study the nature of the shear layer instability. It is found that a counter-current mixing layer is obtained in the upstream shear layer. The corresponding mixing velocity ratio is obtained, and seen to delineate the two regimes of absolute or convective instability. The effect of the nozzle is evaluated by performing simulations without the nozzle while requiring the jet to have the same inlet velocity profile as that obtained at the nozzle exit in the simulations including the nozzle. The shear layer spectra show good agreement with the simulations including the nozzle. The effect of shear layer thickness is studied at a velocity ratio of 2 based on peak and mean jet velocity. The dominant frequencies and spatial shear layer modes from DNS/DMD are significantly altered by the jet exit velocity profile.
This study aimed to compare the interpretations of temporal bone computed tomography scans by an otologist and a radiologist with a special interest in temporal bone imaging. It also aimed to determine the usefulness of this imaging modality.
A head and neck radiologist and an otologist separately reported pre-operative computed tomography images using a structured proforma. The reports were then compared with operative findings to determine their accuracy and differences in interpretations.
Forty-eight patients who underwent pre-operative computed tomography scans in a 30-month period were identified. Six patients were excluded because complete operative findings had not been recorded. Positive and negative predictive values and accuracy of the anatomical and pathological findings were calculated for 42 patients by both reporters. The accuracy was found to be less than 80 per cent, except for identification of the tegmen and lateral semicircular canal erosion. Overall, there was no significant difference in interpretations of computed tomography scans between reporters. There was a slight difference in interpretation for tympanic membrane retraction, facial canal erosion and lateral semicircular canal fistula and/or erosion.
Pre-operative computed tomography scanning of the temporal bone is useful for predicting anatomy for surgical planning in patients with chronic otitis media, but its reliability remains questionable.
Large-eddy simulation (LES) and dynamic mode decomposition (DMD) are used to study an underexpanded sonic jet injected into a supersonic crossflow and an overexpanded supersonic jet injected into a subsonic crossflow, where the flow conditions are based on the experiments of Santiago & Dutton (J. Propul. Power, vol. 13 (2), 1997, pp. 264–273) and Beresh et al. (AIAA J., vol. 43, 2005a, pp. 379–389), respectively. The simulations successfully reproduce experimentally observed shock systems and vortical structures. The time averaged flow fields are compared to the experimental results, and good agreement is observed. The behaviour of the flow is discussed, and the similarities and differences between the two regimes are studied. The trajectory of the transverse jet is investigated. A modification to Schetz et al.’s theory is proposed (Schetz & Billig, J. Spacecr. Rockets, vol. 3, 1996, pp. 1658–1665), which yields good prediction of the jet trajectories in the current simulations in the near field. Point spectra taken at various locations in the flowfield indicate a global oscillation for the sonic jet flow, wherein different regions in the flow oscillate with a frequency of
. For supersonic jet flow, no such global frequency is observed. Dynamic mode decomposition of the three-dimensional pressure field obtained from LES is performed and shows the same behaviour. The DMD results indicate that the
mode is dominant between the upstream barrel shock and the bow shock for the sonic jet, while the roll up of the upstream shear layer is dominant for the supersonic jet.
A systematic review was performed to evaluate the role and effectiveness of head bandages after routine elective middle-ear surgery.
Studies that compared the effectiveness of head bandage use after elective middle-ear surgery (e.g. myringoplasty, mastoidectomy and cochlear implantation) were identified using the following databases: Ovid Medline and Embase, the Ebsco collections, the Cochrane Library, PubMed, and Google Scholar. An initial search identified 71 articles. All titles and abstracts were reviewed. Thirteen relevant articles were inspected in more detail; of these, only five met the inclusion criteria. These included three randomised, controlled trials, one retrospective case series and one literature review.
The three randomised, controlled trials (level of evidence 1b) showed no statistically significant differences in post-operative outcomes (in terms of complications) associated with head bandage use in middle-ear surgery. This finding was supported by the retrospective case series involving patients undergoing cochlear implantation.
Current available evidence shows no advantage of head bandage use after middle-ear surgery. Head bandages may not be required after routine, uncomplicated middle-ear surgery.
The field of electronics packaging is undergoing a significant transition to accommodate the slowing down of lithographically driven semiconductor scaling. Three-dimensional (3D) integration is an important component of this transition and promises to revolutionize the way chips are assembled and interconnected in a subsystem. In this article, we develop the key attributes of 3D integration, the enablers and the challenges that need to be overcome before widespread acceptance by industry. While we are already seeing the proliferation of applications in the memory subsystem, the best is yet to come with the heterogeneous integration of a diverse set of technologies, the mixing of lithographic nodes and an economic argument for its implementation based on overall system function, and cost rather than a narrow component-based analysis. Finally, an extension to monolithic 3D integration promises even further benefits.
In most mental illnesses, onset occurs before the age of 25 and the earliest stages are critical. The youth bear a large share of the burden of disease associated with mental illnesses. Yet, Canadian youths with mental health difficulties face delayed detection; long waiting lists; inaccessible, unengaging services; abrupt transitions between services; and, especially in remoter regions, even a complete lack of services. Responding to this crisis, the Canadian Institutes of Health Research announced a 5-year grant that was awarded to ACCESS, a pan-Canadian network of youths, families, clinicians, researchers, policymakers, community organisations and Indigenous communities. Using strategies developed collaboratively by all stakeholders, ACCESS will execute a youth mental healthcare transformation via early detection, rapid access and appropriate, high-quality care. The project includes an innovative, mixed-methods service research component. Similar in many respects to other national youth mental health initiatives, ACCESS also exhibits important differences of scale, scope and approach.
A primary otological presentation of granulomatosis with polyangiitis is rare. We present four cases of granulomatosis with polyangiitis with different otological manifestations.
A literature review of granulomatosis with polyangiitis cases presenting to otolaryngologists was undertaken. A case series review of four patients presenting within a 12-month period was also performed. One patient had serous otitis media which worsened after myringotomy. Two patients presented with acute ear infection and facial palsy and one with acute mastoiditis. All were positive for antineutrophilic cytoplasmic antibody, and three had positive findings upon histological analysis.
When acute supposed ear infections fail to respond to treatment (antibiotics or surgery), rarer causes of the symptoms should be considered. By reporting this case series, we aim to improve the early diagnosis of granulomatosis with polyangiitis to enable timely treatment and prevent systemic involvement.