Evaluation of laser-glazed plasma-sprayed thermal barriercoatings under high temperature exposure to molten salts

Thermal Barrier Coating (TBC) systems are frequently used in gas turbine engines to provide thermal insulation to the hot-section metallic components and also to protect them from oxidation, hot corrosion and erosion. Surface sealing treatments, namely laser-glazing, have been showing a high potential for extending in-service lifetimes of these systems by improving chemical and thermo-mechanical resistance. In this investigation, both as-sprayed and laser-glazed TBCs were exposed to hot corrosion in molten salts. The glazed coatings were obtained by scanning the surface of the plasma-sprayed coatings with either a CO2 or a Nd:YAG laser. The hot corrosion investigation was accomplished by subjecting the specimens to an isothermal air furnace testing under V2O5 and/or Na2SO4 at a temperature of 1000 °C for 100 h. Spallation has been observed in coatings in the as-sprayed condition under V2O5 or V2O5+Na2SO4. Na2SO4 itself had no or minimal effect on the degradation of the laser-glazed or as-sprayed condition coatings, respectively. The degradation in V2O5 was accomplished by destabilization of YSZ as a consequence of depletion of yttria from the solid solution to form YVO4 and therefore led to the disruptive transformation of the metastable tetragonal phase to the monoclinic phase. Moreover, the presence of both corrosive salts induced the formation of large high aspect ratio YVO4 crystals that introduced additional stresses and contributed to the degradation of the coatings. The laser-glazed specimens were not efficient in avoiding the molten salt penetration along the thickness direction due to the presence of cracks on the glazed layer. However due to a reduced specific surface area of the dense glazed layer, the corrosion reaction of the molten salts with the YSZ has been lower than in coatings in the assprayed condition.Fundo Europeu de Desenvolvimento Regional(FEDER) - Programa Operacional "Ciência, Tecnologia e Inovação" (POCTI).Fundação para a Ciência e a Tecnologia (FCT) - Project POCTI/CTM/ 44590/2002

Allergic fungal sinusitis: CT findings.

PURPOSE : To determine the computed tomographic (CT) findings in patients with allergic fungal sinusitis. MATERIALS AND METHODS: The authors retrospectively reviewed CT scans and surgical and histopathologic reports in 45 patients (27 male, 18 female; age range, 8-68 years) with allergic fungal sinusitis from multiple institutions. The median age (25 years) and demographics of the patients were determined. Two head and neck radiologists together evaluated the CT scans for the presence of intrasinus high-attenuation areas, extent of sinus involvement, bone expansion and thinning, bone erosion, and extension of disease into the adjacent soft tissues. RESULTS: Allergic fungal sinusitis was more common in male patients and in patients aged 20-30 years. All patients had increased intrasinus attenuation at non-contrast material-enhanced CT. Multiple sinus involvement occurred in 43 patients. Bilateral involvement was more common than unilateral disease. Forty-four patients had complete opacification of at least one of the involved sinuses; 43 of these patients had expansion of an involved sinus, 42 had remodeling and thinning of the bony sinus walls, and 41 had erosion of the sinus wall. CONCLUSION: Allergic fungal sinusitis is a distinct clinical entity with nonspecific symptoms that may be initially suggested by the CT findings. These findings should alert the clinician to the possibility of allergic fungal sinusitis and prompt other diagnostic studies to establish the diagnosis and treatment plan

Interim findings from first-dose mass COVID-19 vaccination roll-out and COVID-19 hospital admissions in Scotland: a national prospective cohort study

EAVE II is funded by the Medical Research Council (MR/R008345/1) with the support of BREATHE—The Health Data Research Hub for Respiratory Health (MC_PC_19004), which is funded through the UK Research and Innovation Industrial Strategy Challenge Fund and delivered through Health Data Research UK. Additional support has been provided through Public Health Scotland and the Scottish Government's director-general of Health and Social Care. FDRH acknowledges part support from the National Institutes of Health Research (NIHR) School for Primary Care Research, the NIHR Collaboration for Leadership in Applied Health Research and Care Oxford, and the NIHR Oxford Biomedical Research Centre. SVK acknowledges funding from an NRS Senior Clinical Fellowship (SCAF/15/02), the Medical Research Council (MC_UU_00022/2), and Scottish Government Chief Scientist Office (SPHSU13).Background The BNT162b2 mRNA (Pfizer–BioNTech) and ChAdOx1 nCoV-19 (Oxford–AstraZeneca) COVID-19 vaccines have shown high efficacy against disease in phase 3 clinical trials and are now being used in national vaccination programmes in the UK and several other countries. Studying the real-world effects of these vaccines is an urgent requirement. The aim of our study was to investigate the association between the mass roll-out of the first doses of these COVID-19 vaccines and hospital admissions for COVID-19.  Methods We did a prospective cohort study using the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19—EAVE II—database comprising linked vaccination, primary care, real-time reverse transcription-PCR testing, and hospital admission patient records for 5·4 million people in Scotland (about 99% of the population) registered at 940 general practices. Individuals who had previously tested positive were excluded from the analysis. A time-dependent Cox model and Poisson regression models with inverse propensity weights were fitted to estimate effectiveness against COVID-19 hospital admission (defined as 1–adjusted rate ratio) following the first dose of vaccine.  Findings Between Dec 8, 2020, and Feb 22, 2021, a total of 1 331 993 people were vaccinated over the study period. The mean age of those vaccinated was 65·0 years (SD 16·2). The first dose of the BNT162b2 mRNA vaccine was associated with a vaccine effect of 91% (95% CI 85–94) for reduced COVID-19 hospital admission at 28–34 days post-vaccination. Vaccine effect at the same time interval for the ChAdOx1 vaccine was 88% (95% CI 75–94). Results of combined vaccine effects against hospital admission due to COVID-19 were similar when restricting the analysis to those aged 80 years and older (83%, 95% CI 72–89 at 28–34 days post-vaccination).  Interpretation Mass roll-out of the first doses of the BNT162b2 mRNA and ChAdOx1 vaccines was associated with substantial reductions in the risk of hospital admission due to COVID-19 in Scotland. There remains the possibility that some of the observed effects might have been due to residual confounding.  Funding UK Research and Innovation (Medical Research Council), Research and Innovation Industrial Strategy Challenge Fund, Health Data Research UK.proofPeer reviewe

First dose ChAdOx1 and BNT162b2 COVID-19 vaccinations and cerebral venous sinus thrombosis : a pooled self-controlled case series study of 11.6 million individuals in England, Scotland, and Wales

Funding: This research is part of the Data and Connectivity National Core Study, led by Health Data Research UK in partnership with the Office for National Statistics and funded by UK Research and Innovation (grant ref MC_PC_20029, AS). EAVE II is funded by the Medical Research Council (https://mrc.ukri.org/) (UKRI MC_PC 19075, AS) with the support of BREATHE, The Health Data Research Hub for Respiratory Health (MC_PC_19004, AS), which is funded through the UK Research and Innovation Industrial Strategy Challenge Fund and delivered through Health Data Research UK. This work was supported by the Con-COV team funded by the Medical Research Council (grant number: MR/V028367/1, RL). This work was supported by Health Data Research UK, which receives its funding from HDR UK Ltd (HDR-9006, RL) funded by the UK Medical Research Council, Engineering and Physical Sciences Research Council, Economic and Social Research Council, Department of Health and Social Care (England), Chief Scientist Office of the Scottish Government Health and Social Care Directorates, Health and Social Care Research and Development Division (Welsh Government), Public Health Agency (Northern Ireland), British Heart Foundation (BHF) and the Wellcome Trust. This work was supported by the ADR Wales programme of work (https://www.adruk.org/). ADR Wales is part of the Economic and Social Research Council (part of UK Research and Innovation) funded ADR UK (grant ES/S007393/1, RL). SVK acknowledges funding from NHS Research Scotland Senior Clinical Fellowship (SCAF/15/02, SVK), the MRC (MC_UU_00022/2, SVK), and the Scottish Government Chief Scientist Office (SPHSU17, SVK).Background : Several countries restricted the administration of ChAdOx1 to older age groups in 2021 over safety concerns following case reports and observed versus expected analyses suggesting a possible association with cerebral venous sinus thrombosis (CVST). Large datasets are required to precisely estimate the association between Coronavirus Disease 2019 (COVID-19) vaccination and CVST due to the extreme rarity of this event. We aimed to accomplish this by combining national data from England, Scotland, and Wales. Methods and findings : We created data platforms consisting of linked primary care, secondary care, mortality, and virological testing data in each of England, Scotland, and Wales, with a combined cohort of 11,637,157 people and 6,808,293 person years of follow-up. The cohort start date was December 8, 2020, and the end date was June 30, 2021. The outcome measure we examined was incident CVST events recorded in either primary or secondary care records. We carried out a self-controlled case series (SCCS) analysis of this outcome following first dose vaccination with ChAdOx1 and BNT162b2. The observation period consisted of an initial 90-day reference period, followed by a 2-week prerisk period directly prior to vaccination, and a 4-week risk period following vaccination. Counts of CVST cases from each country were tallied, then expanded into a full dataset with 1 row for each individual and observation time period. There was a combined total of 201 incident CVST events in the cohorts (29.5 per million person years). There were 81 CVST events in the observation period among those who a received first dose of ChAdOx1 (approximately 16.34 per million doses) and 40 for those who received a first dose of BNT162b2 (approximately 12.60 per million doses). We fitted conditional Poisson models to estimate incidence rate ratios (IRRs). Vaccination with ChAdOx1 was associated with an elevated risk of incident CVST events in the 28 days following vaccination, IRR = 1.93 (95% confidence interval (CI) 1.20 to 3.11). We did not find an association between BNT162b2 and CVST in the 28 days following vaccination, IRR = 0.78 (95% CI 0.34 to 1.77). Our study had some limitations. The SCCS study design implicitly controls for variables that are constant over the observation period, but also assumes that outcome events are independent of exposure. This assumption may not be satisfied in the case of CVST, firstly because it is a serious adverse event, and secondly because the vaccination programme in the United Kingdom prioritised the clinically extremely vulnerable and those with underlying health conditions, which may have caused a selection effect for individuals more prone to CVST. Although we pooled data from several large datasets, there was still a low number of events, which may have caused imprecision in our estimates. Conclusions : In this study, we observed a small elevated risk of CVST events following vaccination with ChAdOx1, but not BNT162b2. Our analysis pooled information from large datasets from England, Scotland, and Wales. This evidence may be useful in risk–benefit analyses of vaccine policies and in providing quantification of risks associated with vaccination to the general public.Publisher PDFPeer reviewe

Adult chronic rhinosinusitis

Chronic rhinosinusitis (CRS) occurs in >10% of the adult population in Europe and the USA and can be differentiated into CRS without nasal polyps and CRS with nasal polyps (CRSwNP). Both phenotypes are characterized by a high disease burden and an overlapping spectrum of symptoms, with facial pain and loss of smell being the most differentiating. Great progress has been made in the understanding of CRS pathophysiology: from the epithelium and epithelial-mesenchymal transition to innate and adaptive immunity pathways and, finally, on the role of eosinophils and Staphylococcus aureus in the persistence of disease. Although clinical manifestations and diagnostic tools (including nasal endoscopy and imaging) have undergone major changes over the past few years, management (including pharmacotherapy, surgery and biologics) has experienced enormous progress based on the growing knowledge of key mediators in severe CRSwNP. The introduction of endotyping has led to a differentiation of 'tailored' surgical approaches, focusing on the mucosal concept in those with severe CRSwNP and on the identification of patients eligible for extended surgery and possibly biologics in the future. This Primer on chronic rhinosinusitis summarizes the epidemiology, physiology, diagnosis and management of this disorder and discusses the quality of life of patients with this condition

Medical treatment of epistaxis in hereditary hemorrhagic telangiectasia: an evidence-based review

Background: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant hereditary disorder resulting in vascular dysplasia and formation of arteriovenous malformations. Recurrent epistaxis is a hallmark of the disease. An array of medical therapies are used in this patient population, but robust evidence-based recommendations regarding the medical treatment of epistaxis are lacking. This systematic review was performed to look at the current literature and make meaningful evidence-based recommendations. Methods: A search of the Ovid MEDLINE, Embase, and Cochrane databases was conducted by a research librarian. Abstracts in the English language and published in a peer-review journal were reviewed for relevance and inclusion. PRISMA guidelines were followed. Results: Eighteen studies met the inclusion criteria. In a few small studies, thalidomide was shown to consistently improve severity and frequency of epistaxis and improve hemoglobin concentrations while decreasing the need for transfusion. Tranexamic acid appeared to only impact the epistaxis severity score and not other clinical outcomes. Selective estrogen modulators (SERMs), propranolol, rose geranium oil, and N-acetylcysteine, have demonstrated promising efficacy in small trials. Conclusion: Appropriate medical therapies for epistaxis outcomes in HHT remain undefined, and there is no gold standard. Many of the studies are small and the data reported are heterogeneous, and therefore the ability to make strong evidence-based recommendations is limited. However, many different medications appear to be promising option

Rhinosinusitis: Establishing definitions for clinical research and patient care

Objectives: to develop consensus definitions for rhinosinusitis and outline strategies useful in clinical trial