Experimental and CFD analysis of the wake characteristics of tidal turbines

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This paper investigates the accuracy of the Computational Fluid Dynamics (CFD) based Immersed Body Force (IBF) turbine modelling method for predicting the flow characteristics of a Momentum-Reversal-Lift type of tidal turbine. This empirically-based CFD model has been developed based on the actuator disc method enhanced with additional features to mimic the effect of the complex blade motion on the downstream wake, without the high computational costs of explicitly modelling the dynamic blade motion. The model has been calibrated against the flow characteristics data obtained from experiment and found to perform well, although there are few inconsistencies in the flow patterns which show some of the limitations of the IBF model compared to a full dynamic blade motion simulation. However, given the complexity and computational cost of modelling the detailed blade motion the limitations of the IBF model are acceptable and will be useful especially for optimisation of arrays of devices where there is a significant computational demand.We would like to thank EPSRC for providing the funding under project number EP/J010138/1, as part of the Supergen Marine research program and the IFREMER personnel of Boulogne-sur-Mer for their assistance and advice during the experimental trials

Determining the chemical exchange saturation transfer (CEST) behavior of citrate and spermine under in vivo conditions.

Purpose To estimate the exchange rates of labile (1) H in citrate and spermine, metabolites present in prostatic secretions, to predict the size of the citrate and spermine CEST effects in vivo.Methods CEST z-spectra were acquired at high-field [11.7 Tesla (T)] from citrate and spermine solutions at physiological pH (6.5) using saturation power 6 μT. CEST was performed at different temperatures to determine exchange regimes (slow, intermediate or fast). For low pH solutions of spermine, exchange rates were estimated from resonance line width, fitting z-spectra using the Bloch equations incorporating exchange, and using quantifying exchange using saturation time experiments (QUEST). These rates were extrapolated to physiological pH.Results Citrate showed little CEST effect at pH 6.5 and temperature (T) = 310 K (maximum 0.001% mM(-1) ), indicating fast exchange, whereas spermine showed greater CEST effects (maximum 0.2% mM(-1) ) indicating intermediate-to-fast exchange. Extrapolating data acquired from low pH spermine solutions predicts exchange rates at pH 6.5 and T of 310 K of at least 2 × 10(4) s(-1) .Conclusion Citrate and spermine show minimal CEST effects at 11.7T even using high saturation power. These effects would be much less than 2% at clinical field-strengths due to relatively faster exchange and would be masked by CEST from proteins. Magn Reson Med 76:742-746, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

Poverty, Education, and Cultural Wealth in Welsh Schools and Communities

This paper explores community bonds, divisions and the cultural aspirations of young people in Welsh schools. It draws, in particular, on data on how teachers view support given to those in varying extents of poverty, especially focusing on those have with little cultural, parental, school, and community supports. The paper will outline the exclusionary impacts of social and educational measures of poverty, showing how these shape school responses and community resources. Using Yosso's ideas of cultural wealth to examine key themes emerging from the study cultural, i.e. aspirational, navigational, social, linguistic, familial and resistant forms of social and cultural capital, we will highlight the types of support needed for parents, young people and teachers to develop forms of cultural and social capital which might shape stronger resources towards the achievement of individual and community aspiration

Comparison of three reference methods for the measurement of intracellular pH using 31P MRS in healthy volunteers and patients with lymphoma.

31P magnetic resonance spectroscopy (31P MRS) can measure intracellular pH (pHi) using the chemical shift difference between pH-dependent inorganic phosphate (Pi) and a pH-independent reference peak. This study compared three different frequency reference peaks [phosphocreatine (PCr), α resonance of adenosine triphosphate (αATP) and water (using 1H MRS)] in a cohort of 10 volunteers and eight patients with non-Hodgkin's lymphoma (NHL). Well-resolved chemical shift imaging (CSI) spectra were acquired on a 1.5T scanner for muscle, liver and tumour. The pH was calculated for all volunteers and patients using the available methods. The consistency of the resulting pH was evaluated. The direct Pi–PCr method was best for those spectra with a very well-defined PCr, such as muscle (pH=7.05 ± 0.02). In liver, the Pi–αATP method gave more consistent results (pH=7.30 ± 0.06) than the calibrated water-based method (pH=7.27 ± 0.11). In NHL nodes, the measured pH using the Pi–αATP method was 7.25 ± 0.12. Given that the measured range includes some biological variation in individual patients, treatment-related changes of the order of 0.1 pH units should be detectable

An assessment of pulse transit time for detecting heavy blood loss during surgical operation

Copyright @ Wang et al.; Licensee Bentham Open. This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.The main contribution of this paper is the use of non-invasive measurements such as electrocardiogram (ECG) and photoplethysmographic (PPG) pulse oximetry waveforms to develop a new physiological signal analysis technique for detecting blood loss during surgical operation. Urological surgery cases were considered as the control group due to its generality, and cardiac surgery as experimental group since it involves blood loss and water supply. Results show that the control group has the tendency of a reduction of the pulse transient time (PTT), and this indicates an increment in the blood flow velocity changes from slow to fast. While for the experimental group, the PTT indicates high values during blood loss, and low values during water supply. Statistical analysis shows considerable differences (i.e., P <0.05) between both groups leading to the conclusion that PTT could be a good indicator for monitoring patients' blood loss during a surgical operation.The National Science Council (NSC) of Taiwan and the Centre for Dynamical Biomarkers and Translational Medicine, National Central University, Taiwan

Factors Associated With Engagement With a Web-Based Lifestyle Intervention Following Provision of Coronary Heart Disease Risk: Mixed Methods Study

Background: Web-based interventions provide the opportunity to combine the tailored approach of face-to-face interventions with the scalability and cost-effectiveness of public health interventions. This potential is often limited by low engagement. A number of studies have described the characteristics of individuals who engage more in Web-based interventions but few have explored the reasons for these variations. Objective: We aimed to explore individual-level factors associated with different degrees of engagement with a Web-based behavior change intervention following provision of coronary heart disease (CHD) risk information, and the barriers and facilitators to engagement. Methods: This study involved the secondary analysis of data from the Information and Risk Modification Trial, a randomized controlled trial of a Web-based lifestyle intervention alone, or alongside information on estimated CHD risk. The intervention consisted of three interactive sessions, each lasting up to 60 minutes, delivered at monthly intervals. Participants were characterized as high engagers if they completed all three sessions. Thematic analysis of qualitative data from interviews with 37 participants was combined with quantitative data on usage of the Web-based intervention using a mixed-methods matrix, and data on the views of the intervention itself were analyzed across all participants. Results: Thirteen participants were characterized as low engagers and 24 as high engagers. There was no difference in age (P=.75), gender (P=.95), or level of risk (P=.65) between the groups. Low engagement was more often associated with: (1) reporting a negative emotional reaction in response to the risk score (P=.029), (2) perceiving that the intervention did not provide any new lifestyle information (P=.011), and (3) being less likely to have reported feeling an obligation to complete the intervention as part of the study (P=.019). The mixed-methods matrix suggested that there was also an association between low engagement and less success with previous behavior change attempts, but the statistical evidence for this association was weak (P=.16). No associations were seen between engagement and barriers or facilitators to health behavior change, or comments about the design of the intervention itself. The most commonly cited barriers related to issues with access to the intervention itself: either difficulties remembering the link to the site or passwords, a perceived lack of flexibility within the website, or lack of time. Facilitators included the nonjudgmental presentation of lifestyle information, the use of simple language, and the personalized nature of the intervention. Conclusions: This study shows that the level of engagement with a Web-based intervention following provision of CHD risk information is not influenced by the level of risk but by the individual’s response to the risk information, their past experiences of behavior change, the extent to which they consider the lifestyle information helpful, and whether they felt obliged to complete the intervention as part of a research study. A number of facilitators and barriers to Web-based interventions were also identified, which should inform future interventions.The INFORM study was funded by European Commission Framework 7 EPIC-CVD Grant agreement (No. 279233). NHS Blood and Transplant funded the INTERVAL trial. Deoxyribonucleic acid extraction and genotyping in INTERVAL/INFORM was funded by the United Kingdom National Institute of Health Research. The coordinating team for INTERVAL/INFORM at the Cardiovascular Epidemiology Unit of the University of Cambridge was supported by core funding from: United Kingdom Medical Research Council (G0800270), British Heart Foundation (SP/09/002), British Heart Foundation Cambridge Cardiovascular Centre of Excellence, and United Kingdom National Institute for Health Research Cambridge Biomedical Research Centre. JUS was funded by a National Institute for Health Clinical Lectureship and BS was supported by the Medical Research Council (MC_UU_12015/4)

Distortion correction of echo-planar diffusion-weighted images of uterine cervix.

To investigate the clinical utility of the reverse gradient algorithm in correcting distortions in diffusion-weighted images of the cervix and for increasing diagnostic performance.Forty-one patients ages 25-72 years (mean 40 ± 11 years) with suspected or early stage cervical cancer were imaged at 3T using an endovaginal coil. T2 -weighted (W) and diffusion-weighted images with right and left phase-encode gradient directions were obtained coronal to the cervix (b = 0, 100, 300, 500, 800 s mm(-2) ). Differences in angle of the endocervical canal to the x-axis between T2 W and right-gradient, left-gradient, and corrected images were measured. Uncorrected and corrected images were assessed for diagnostic performance when viewed together with T2 W images by two independent observers against subsequent histology.The angles of the endocervical canal relative to the x-axis were significantly different between the T2 W images and the right-gradient images (P = 0.007), approached significance for left-gradient images (P = 0.055), and were not significantly different after correction (P = 0.95). Corrected images enabled a definitive diagnosis in 34% (n = 14) of patients classified as equivocal on uncorrected images. Tumor volume in this subset was 0.18 ± 0.44 cm(3) (mean ± SD; sensitivity of detection 100% [8/8], specificity 50% [3/6] for an experienced observer). Correction did not improve diagnostic performance for the less-experienced observer.Distortion-corrected diffusion-weighted images improved correspondence with T2 W images and diagnostic performance in a third of cases

Factors affecting exhaled nitric oxide measurements: the effect of sex

<p>Abstract</p> <p>Background</p> <p>Exhaled nitric oxide (F_ENO) measurements are used as a surrogate marker for eosinophilic airway inflammation. However, many constitutional and environmental factors affect F_ENO, making it difficult to devise reference values. Our aim was to evaluate the relative importance of factors affecting F_ENO in a well characterised adult population.</p> <p>Methods</p> <p>Data were obtained from 895 members of the Dunedin Multidisciplinary Health and Development Study at age 32. The effects of sex, height, weight, lung function indices, smoking, atopy, asthma and rhinitis on F_ENO were explored by unadjusted and adjusted linear regression analyses.</p> <p>Results</p> <p>The effect of sex on F_ENO was both statistically and clinically significant, with F_ENO levels approximately 25% less in females. Overall, current smoking reduced F_ENO up to 50%, but this effect occurred predominantly in those who smoked on the day of the F_ENO measurement. Atopy increased F_ENO by 60%. The sex-related differences in F_ENO remained significant (p < 0.001) after controlling for all other significant factors affecting F_ENO.</p> <p>Conclusion</p> <p>Even after adjustment, F_ENO values are significantly different in males and females. The derivation of reference values and the interpretation of F_ENO in the clinical setting should be stratified by sex. Other common factors such as current smoking and atopy also require to be taken into account.</p