Computational prediction of the refinement of oxide agglomerates in a physical conditioning process for molten aluminium alloy

Physically conditioning molten scrap aluminium alloys using high shear processing (HSP) was recently found to be a promising technology for purification of contaminated alloys. HSP refines the solid oxide agglomerates in molten alloys, so that they can act as sites for the nucleation of Fe-rich intermetallic phases which can subsequently be removed by the downstream de-drossing process. In this paper, a computational modelling for predicting the evolution of size of oxide clusters during HSP is presented. We used CFD to predict the macroscopic flow features of the melt, and the resultant field predictions of temperature and melt shear rate were transferred to a population balance model (PBM) as its key inputs. The PBM is a macroscopic model that formulates the microscopic agglomeration and breakage of a population of a dispersed phase. Although it has been widely used to study conventional deoxidation of liquid metal, this is the first time that PBM has been used to simulate the melt conditioning process within a rotor/stator HSP device. We employed a method which discretizes the continuous profile of size of the dispersed phase into a collection of discrete bins of size, to solve the governing population balance equation for the size of agglomerates. A finite volume method was used to solve the continuity equation, the energy equation and the momentum equation. The overall computation was implemented mainly using the FLUENT module of ANSYS. The simulations showed that there is a relatively high melt shear rate between the stator and sweeping tips of the rotor blades. This high shear rate leads directly to significant fragmentation of the initially large oxide aggregates. Because the process of agglomeration is significantly slower than the breakage processes at the beginning of HSP, the mean size of oxide clusters decreases very rapidly. As the process of agglomeration gradually balances the process of breakage, the mean size of oxide clusters converges to a steady value. The model enables formulation of the quantitative relationship between the macroscopic flow features of liquid metal and the change of size of dispersed oxide clusters, during HSP. It predicted the variation in size of the dispersed phased with operational parameters (including the geometry and, particularly, the speed of the rotor), which is of direct use to experimentalists optimising the design of the HSP device and its implementation.This research is financially supported by the EC FP7 project “High Shear Processing of Recycled Aluminium Scrap for Manufacturing High Performance Aluminium Alloys” (Grant No. 603577)

Management of thyroglossal tract disease after failed Sistrunk’s procedure

Sistrunk’s procedure for thyroglossal duct remnants has a very high success rate, there remains the occasional patient, however, that will have recurrent disease despite a competently performed operation. Applied anatomy and embryology proffer a solution to this problem. Extending the Sistrunk operation, with an anterior wide local excision remaining within normal tissue, enables removal of the entire thyroglossal tract remnant. A retrospective case note review was conducted to study our experience using this extended procedure to treat patients with thyroglossal tract disease that had recurred after a previous Sistrunk’s operation. Six patients aged from five to 33 years were included in the study. There was one recurrence and the complication rate was comparable to the standard operation. It was concluded that a wide local excision is a valuable extension of the Sistrunk operation for the management of recurrent disease

Diffusion tensor imaging reveals changes in microstructural integrity along compressed nerve roots that correlate with chronic pain symptoms and motor deficiencies in elderly stenosis patients

Age-related degenerative changes in the lumbar spine frequently result in nerve root compression causing severe pain and disability. Given the increasing incidence of lumbar spinal disorders in the aging population and the discrepancies between the use of current diagnostic imaging tools and clinical symptoms, novel methods of nerve root assessment are needed. We investigated elderly patients with stenosis at L4-L5 or L5-S1 levels. Diffusion tensor imaging (DTI) was used to quantify microstructure in compressed L5 nerve roots and investigate relationships to clinical symptoms and motor neurophysiology. DTI metrics (i.e. FA, MD, AD and RD) were measured at proximal, mid and distal segments along compressed (i.e. L5) and intact (i.e. L4 or S1) nerve roots. FA was significantly reduced in compressed nerve roots and MD, AD and RD were significantly elevated in the most proximal segment of the nerve root studied. FA was significantly correlated with electrophysiological measures of root function: minimum F-wave latency and peripheral motor conduction time (PMCT). In addition, FA along the compressed root also correlated with leg pain and depression score. There was also a relationship between RD and anxiety, leg pain and disability score and AD correlated with depression score. Taken together, these data show that DTI metrics are sensitive to nerve root compression in patients with stenosis as a result of age-related lumbar degeneration. Critically, they show that the changes in microstructural integrity along compressed L5 nerve roots are closely related to a number of clinical symptoms associated with the development of chronic pain as well as neurophysiological assessments of motor function. These inherent relationships between nerve root damage and phenotype suggest that the use DTI is a promising method as a way to stratify treatment selection and predict outcomes

Arterial Recanalization for Access for Arterial Intervention in Children: Techniques and Outcomes

PURPOSE: To assess technical success of arterial recanalization in children requiring repeated arterial access and intervention. MATERIALS AND METHODS: Over 14 years, 41 attempts to cross 30 arterial occlusions were made in 22 patients (13 male, 9 female). Median patient age was 12 months (15 days-14 years), and weight was 7.6 kg (3.0-77.3 kg). Techniques and outcomes were recorded. RESULTS: Twenty-five of 41 (61%) attempts at crossing an arterial occlusion were successful. Nineteen of 30 (63%) first attempts to cross occlusions were successful, and 6 of 11 (55%) repeat attempts were successful. The occluded segments were combinations of common femoral artery (n = 4), external iliac artery (n = 36), common iliac artery (n = 11), and aorta (n = 1). Complications occurred in 5 of 41(12%) attempts: 3 minor complications (hematoma, extravasation, and transient leg ischemia) and 2 major complications (rupture and thrombosis). CONCLUSIONS: Arterial access by recanalization of occluded segments is technically feasible in children, with a low complication rate

A cost effectiveness and capacity analysis for the introduction of universal rotavirus vaccination in Kenya : comparison between Rotarix and RotaTeq vaccines

Background Diarrhoea is an important cause of death in the developing world, and rotavirus is the single most important cause of diarrhoea associated mortality. Two vaccines (Rotarix and RotaTeq) are available to prevent rotavirus disease. This analysis was undertaken to aid the decision in Kenya as to which vaccine to choose when introducing rotavirus vaccination. Methods Cost-effectiveness modelling, using national and sentinel surveillance data, and an impact assessment on the cold chain. Results The median estimated incidence of rotavirus disease in Kenya was 3015 outpatient visits, 279 hospitalisations and 65 deaths per 100,000 children under five years of age per year. Cumulated over the first five years of life vaccination was predicted to prevent 34% of the outpatient visits, 31% of the hospitalizations and 42% of the deaths. The estimated prevented costs accumulated over five years totalled US$1,782,761 (direct and indirect costs) with an associated 48,585 DALYs. From a societal perspective Rotarix had a cost-effectiveness ratio of US$142 per DALY (US$5 for the full course of two doses) and RotaTeq US$288 per DALY ($10.5 for the full course of three doses). RotaTeq will have a bigger impact on the cold chain compared to Rotarix. Conclusion Vaccination against rotavirus disease is cost-effective for Kenya irrespective of the vaccine. Of the two vaccines Rotarix was the preferred choice due to a better cost-effectiveness ratio, the presence of a vaccine vial monitor, the requirement of fewer doses and less storage space, and proven thermo-stability

Abrasive water jet drilling of advanced sustainable bio-fibre-reinforced polymer/hybrid composites : a comprehensive analysis of machining-induced damage responses

This paper aims at investigating the effects of variable traverse speeds on machining-induced damage of fibre-reinforced composites, using the abrasive water jet (AWJ) drilling. Three different types of epoxy-based composites laminates fabricated by vacuum bagging technique containing unidirectional (UD) flax, hybrid carbon-flax and carbon fibre-reinforced composite were used. The drilling parameters used were traverse speeds of 20, 40, 60 and 80 mm/min, constant water jet pressure of 300 MPa and a hole diameter of 10 mm. The results obtained depict that the traverse speed had a significant effect with respect to both surface roughness and delamination drilling-induced damage responses. Evidently, an increase in water jet traverse speed caused an increase in both damage responses of the three samples. Significantly, the CFRP composite sample recorded the lowest surface roughness damage response, followed by C-FFRP, while FFRP exhibited the highest. However, samples of FFRP and hybrid C-FFRP recorded lowest and highest delamination damage responses, respectively. The discrepancy in both damage responses, as further validated with micrographs of colour video microscopy (CVM), scanning electron microscopy (SEM) and X-ray micro-computed tomography (X-ray μCT), is attributed to the different mechanical properties of the reinforced fibres, fibre orientation/ply stacking and hybridisation of the samples.Peer reviewe

Zofenopril Protects Against Myocardial Ischemia-Reperfusion Injury by Increasing Nitric Oxide and Hydrogen Sulfide Bioavailability.

Background: Zofenopril, a sulfhydrylated angiotensin-converting enzyme inhibitor (ACEI), reduces mortality and morbidity in infarcted patients to a greater extent than do other ACEIs. Zofenopril is a unique ACEI that has been shown to increase hydrogen sulfide (H2S) bioavailability and nitric oxide (NO) levels via bradykinin-dependent signaling. Both H2S and NO exert cytoprotective and antioxidant effects. We examined zofenopril effects on H2S and NO bioavailability and cardiac damage in murine and swine models of myocardial ischemia/reperfusion (I/R) injury. Methods and results: Zofenopril (10 mg/kg PO) was administered for 1, 8, and 24 hours to establish optimal dosing in mice. Myocardial and plasma H2S and NO levels were measured along with the levels of H2S and NO enzymes (cystathionine β-synthase, cystathionine γ-lyase, 3-mercaptopyruvate sulfur transferase, and endothelial nitric oxide synthase). Mice received 8 hours of zofenopril or vehicle pretreatment followed by 45 minutes of ischemia and 24 hours of reperfusion. Pigs received placebo or zofenopril (30 mg/daily orally) 7 days before 75 minutes of ischemia and 48 hours of reperfusion. Zofenopril significantly augmented both plasma and myocardial H2S and NO levels in mice and plasma H2S (sulfane sulfur) in pigs. Cystathionine β-synthase, cystathionine γ-lyase, 3-mercaptopyruvate sulfur transferase, and total endothelial nitric oxide synthase levels were unaltered, while phospho-endothelial nitric oxide synthase(1177) was significantly increased in mice. Pretreatment with zofenopril significantly reduced myocardial infarct size and cardiac troponin I levels after I/R injury in both mice and swine. Zofenopril also significantly preserved ischemic zone endocardial blood flow at reperfusion in pigs after I/R. Conclusions: Zofenopril-mediated cardioprotection during I/R is associated with an increase in H2S and NO signaling

A review of standard pharmacological therapy for adult asthma - Steps 1 to 5

The aim of pharmacological therapy for asthma is to improve symptoms and lung function and minimise the risk of asthma attacks. The intensity of treatment is based on the level of asthma control and the potential risk of future deterioration. In the British asthma guidelines, treatments are divided into Step One to Five, with each Step signifying a need for an increase in therapy in response to symptoms or to prevent exacerbations. Treatments comprise of inhaled or systemic medications. Inhaled therapy includes short-acting and long-acting medication to improve symptoms and inhaled corticosteroids which reduce airway inflammation. Systemic treatments include medications which act on specific biological pathways, such as the leukotriene or IgE pathways, or systemic corticosteroids. In choosing a particular therapy, treatment benefits are balanced by the potential risks of medication-related adverse effects. This review will provide a practical guide to the key pharmacological therapies for adult asthma at Steps One to Five based on British guidelines and consider future options for new treatments

Predicting Incremental and Future Visual Change in Neovascular Age-Related Macular Degeneration Using Deep Learning

PURPOSE: To evaluate the predictive utility of quantitative imaging biomarkers, acquired automatically from optical coherence tomography (OCT) scans, of cross-sectional and future visual outcomes of patients with neovascular age-related macular degeneration (AMD) starting anti-vascular endothelial growth factor (VEGF) therapy. DESIGN: Retrospective cohort study. PARTICIPANTS: Treatment-naïve, first-treated eyes of patients with neovascular AMD between 2007 and 2017 at Moorfields Eye Hospital (a large, UK single-centre) undergoing anti-VEGF therapy METHODS: Automatic segmentation was carried out by applying a deep learning segmentation algorithm to 137,379 OCT scans from 6467 eyes of 3261 patients with neovascular AMD. After applying selection criteria 926 eyes of 926 patients were taken forward for analysis. MAIN OUTCOME MEASURES: Correlation coefficients (R2) and mean absolute error (MAE) between quantitative OCT (qOCT) parameters and cross-sectional visual-function. The predictive value of these parameters for short-term visual change i.e. incremental visual acuity [VA] resulting from an individual injection, as well as, VA at distant timepoints (up to 12 months post-baseline). RESULTS: VA at distant timepoints could be predicted: R2 0.80 (MAE 5.0 ETDRS letters) and R2 0.7 (MAE 7.2) post-injection 3 and at 12 months post-baseline (both p < 0.001), respectively. Best performing models included both baseline qOCT parameters and treatment-response. Furthermore, we present proof-of-principle evidence that the incremental change in VA from an injection can be predicted: R2 0.14 (MAE 5.6) for injection 2 and R2 0.11 (MAE 5.0) for injection 3 (both p < 0.001). CONCLUSIONS: Automatic segmentation enables rapid acquisition of quantitative and reproducible OCT biomarkers with potential to inform treatment decisions in the care of neovascular AMD. This furthers development of point-of-care decision-aid systems for personalized medicine

Worldwide trends in mortality from biliary tract malignancies

BACKGROUND: Intrahepatic cholangiocarcinomas are malignant tumors arising from the intrahepatic biliary tract. The pathogenesis of these tumors remains unknown. Although there is a marked global variation in prevalence, some recent studies have suggested an increase in mortality from intrahepatic cholangiocarcinoma in several regions of low endemicity. As the study of mortality trends may yield clues to possible etiological factors, we analyzed worldwide time trends in mortality from biliary tract malignancies. METHODS: Annual age-standardized rates for individual countries were compiled for deaths from biliary tract malignancies using the WHO database. These data were used to analyze gender and site-specific trends in mortality rates. RESULTS: An increasing trend for mortality from intrahepatic cholangiocarcinoma was noted in most countries. The average estimated annual percentage change (EAPC) in mortality rates for males was 6.9 ± 1.5, and for females was 5.1 ± 1.0. Increased mortality rates were observed in all geographic regions. Within Europe, increases were higher in Western Europe than in Central or Northern Europe. In contrast, mortality rates for extrahepatic biliary tract malignancies showed a decreasing trend in most countries, with an overall average EAPC of -0.3 ± 0.4 for males, but -1.3 ± 0.4 for females. CONCLUSIONS: There has been a marked global increase in mortality from intrahepatic, but not extra-hepatic, biliary tract malignancies