Increased expression of circulating miRNA-93 in women with polycystic ovary syndrome may represent a novel, non-invasive biomarker for diagnosis

MicroRNAs (miRNA) are a novel class of small noncoding single-stranded RNA molecules that regulate gene expression. There is increasing evidence of their importance in polycystic ovary syndrome (PCOS). The objective was to determine if miRNA-93 and miRNA-223 are differentially expressed in the circulation of women with PCOS compared to age matched women. A case–control study comparing women with PCOS (n = 25) to age and weight matched controls (n = 24) without PCOS was performed. MiRNA-93 and miRNA-223 were determined by total RNA reverse transcription. Both miRNA-93 and miRNA-223 were significantly increased relative to the control group (p < 0.01, p = 0.029 respectively). In both groups there was no correlation of either miRNA-93 or miRNA-223 with insulin, HOMA-IR, HOMA-β or testosterone levels. The area under the receiver operator characteristic curve for miR-223 and miR-93 was 0.66 and 0.72 respectively, suggesting miR-93 is a more efficient biomarker than miR-223 for diagnosis of PCOS. The combination of the two miRNAs together, tested using multiple logistic regression analysis, did not improve the diagnostic potential. In conclusion, circulating miRNA-93 and miRNA-223 were higher in women with PCOS compared to age and weight matched controls independent of insulin resistance and testosterone levels, and miR-93 may represent a novel diagnostic biomarker for PCOS

Measurement and modelling of the turbulent boundary layer near the attachment line of a swept wing

This work is motivated by the need for low-order aerodynamic models to predict accurately the effect on profile drag of controlling attachment line transition. Head's entrainment method (1) , a rapid integral boundary layer technique used for design studies on swept wings, suffers from the governing swept-tapered turbulent integral boundary layer equations being ill-posed in the vicinity of the attachment line. This singularity has been treated using crude extrapolations of the attachment-line similarity solution for over half a century, but this approach is unlikely to deliver accurate predictions of the effect of changes in the attachment line flow on profile drag. An experimental study has been carried out to explore the nature of the turbulent flow in the vicinity of a highly swept swept attachment line and has revealed a quite complex, non-monotonic development of the momentum thickness in this region. It has also revealed lower levels of twist in the boundary layer velocity profiles than anticipated from the highly curved character of the inviscid flow streamlines. These observations have prompted an alternative approach to the modelling of the flow in this region which not only successfully eliminates the lack of robustness in the swept-tapered equations but which also matches the experimental results to within ±5%

Incompressible turbulent flow at the leading edge of swept wings

Due to a singularity in the governing three-dimensional turbulent momentum integral equations at the attachment line, low order infinite-swept and swept-tapered CFD methods employing the viscous-coupling technique have been unable to model attachment line transition or contamination without approximating the development of the boundary layer immediately downstream of a turbulent attachment line. An experimental study was therefore conducted to explore the flow near a turbulent attachment line, which showed considerable differences to the numerical approximation. On the basis of the experimental data; a modification to the governing equations in the attachment line region has been proposed and tested. Comparisons with experimental measurements show that the proposed numerical model is not only able to predict the flow to within ±5%, but it also captures the non-monotonic behaviour of the momentum thickness, in the vicinity of the attachment line, which has not been reported previously

Recent Developlments to the viscous Garabedian and Korn method

This paper describes recent developments to the legacy VGK method based upon a new coupling with the Callisto boundary layer code developed for Airbus. The new CVGK method has been compared against its predecessor and validated against a transonic swept-wing dataset. Various conceptual studies have then been carried out to model the effect on form drag (viscous pressure drag) of changes to boundary layer entrainment and shock-control ramps. It is concluded that there are both risks to, and opportunities for, drag reduction techniques associated with managing the form drag contribution from the aft region of highly-loaded transonic aerofoils

The trade-off between taxi time and fuel consumption in airport ground movement

Environmental impact is a very important agenda item in many sectors nowadays, which the air transportation sector is also trying to reduce as much as possible. One area which has remained relatively unexplored in this context is the ground movement problem for aircraft on the airport’s surface. Aircraft have to be routed from a gate to a runway and vice versa and it is still unknown whether fuel burn and environmental impact reductions will best result from purely minimising the taxi times or whether it is also important to avoid multiple acceleration phases. This paper presents a newly developed multi-objective approach for analysing the trade-off between taxi time and fuel consumption during taxiing. The approach consists of a combination of a graph-based routing algorithm and a population adaptive immune algorithm to discover different speed profiles of aircraft. Analysis with data from a European hub airport has highlighted the impressive performance of the new approach. Furthermore, it is shown that the trade-off between taxi time and fuel consumption is very sensitive to the fuel-related objective function which is used

On the turbulent mean-flow at the leading edge of a swept wing

Due to the presence of a singularity in the governing three-dimensional (3D) momentum integral equation at the attachment line (AL) and numerical issues while marching immediately downstream, a numerical fix was previously imposed in the leading edge (LE) modelling of Airbus Callisto. This technique has been employed for half a century during the design and optimisation of transonic wings, but recent analysis on AL control for form drag reduction rose concerns about this previously accepted numerical fix. An experimental study was conducted to validate this LE approximation. Measurement of the boundary layer integral quantities immediately downstream of the AL showed considerable increment; therefore a modification to the 3D governing equation was suggested to remove the numerical fix in the LE modelling. Comparison with experimental measurements showed that the proposed numerical model is not only able to predict the flow within an agreement of ±5%, but it is also able to capture the non-monotonic behaviour in the development of the momentum thickness in the vicinity of the AL, not reported previously

On the excitation of Tollmien-Schlichting waves due to surface vibration

The effect of localised surface vibration on the stability of a Blasius boundary layer was studied. First it was demonstrated that small amplitude vibration of the order of less than 10µm can artificially excite Tollmien-Schlichting (TS) waves provided that the frequency of excitation was within the frequency band of the naturally occurring disturbance in the freestream environment. Longitudinally aligned motors generated more energetic TS wave and the growth rate increased with increasing number of live motors. But when a combination of both longitudinally and transversely align motors was tested a reduction in the growth rate was observed even when the total number of motors was larger than the most amplified case which was generated by 5 motors along the longitudinal axis

Coupling of hard dimers to dynamical lattices via random tensors

We study hard dimers on dynamical lattices in arbitrary dimensions using a random tensor model. The set of lattices corresponds to triangulations of the d-sphere and is selected by the large N limit. For small enough dimer activities, the critical behavior of the continuum limit is the one of pure random lattices. We find a negative critical activity where the universality class is changed as dimers become critical, in a very similar way hard dimers exhibit a Yang-Lee singularity on planar dynamical graphs. Critical exponents are calculated exactly. An alternative description as a system of `color-sensitive hard-core dimers' on random branched polymers is provided.Comment: 12 page

Patient-reported outcomes following flexible sigmoidoscopy screening for colorectal cancer in a demonstration screening programme in the UK

<p>OBJECTIVES: Flexible sigmoidoscopy (FS) screening for colorectal cancer will be introduced into the National Cancer Screening Programmes in England in 2013. Patient-reported outcome measures (PROMs) from trial participants indicate high acceptability and no adverse physical or psychological consequences, but this may not generalize to routine screening in the community. This study examined PROMs in a community-based FS screening programme.</p> <p>METHODS: Eligible adults aged 58-59 (n = 2016) registered at 34 London general practices were mailed a National Health Service-endorsed invitation to attend FS screening. Pain and side-effects were assessed in a 'morning-after' questionnaire, and satisfaction was assessed in a three-month follow-up questionnaire. Anxiety, self-rated health and colorectal symptoms were assessed at prescreening and follow-up.</p> <p>RESULTS: In total, 1020 people attended screening and were included in the current analyses, of whom 913 (90%) returned the morning-after questionnaire, and 674 (66%) the follow-up questionnaire. The prescreening questionnaire had been completed by 751 (74%) of those who attended. The majority (87%) of respondents reported no pain or mild pain, and the most frequent side-effect (wind) was only experienced more than mildly by 16%. Satisfaction was extremely high, with 98% glad they had the test; 97% would encourage a friend to have it. From prescreening to follow-up there were no changes in anxiety or self-rated health, and the number of colorectal symptoms declined. Satisfaction and changes in wellbeing were not moderated by gender, deprivation, ethnicity or screening outcome.</p> <p>CONCLUSIONS: PROMs indicate high acceptability of FS screening in 58-59 year olds, with no adverse effects on colorectal symptoms, health status or psychological wellbeing.</p&gt

Development of a quantitative Schlieren imaging technicque for acoustic waves

The primary objective of the present work was the development of a quantitative schlieren-imaging technique that can be used to study the dynamics of instability waves. An underexpanded jet was considered as an ideal test case due to the complexity and multitude of instability mechanism. The technique was initially validated by optically capturing a controlled acoustic wave generated by a compression driver and excellent agreement was obtained with microphone measurements. Further analysis of an underexpanded jet demonstrated that the technique can be used to capture the very high screech frequency