A cross-correlation digital particle image velocimetry ( PIV ) system has been developed and applied to study the in-cylinder ow in a single-cylinder engine with a production-type cylinder head. The PIV system set-up and its optimization are described in the rst part of the paper. Twodimensional velocity distributions measured over 100 cycles are analysed to obtain ensemble-averaged mean and uctuating velocities, the turbulent length scale, vorticity and strain rate distribution in the measurement plane. In particular, a spatial ltering scheme is developed in order to obtain the cycle-resolved velocity measurements. The cycle-resolved analysis shows that the low-frequency velocity uctuation component (i.e. cyclic variation) is mainly responsible for the spatial variation in velocity and turbulent kinetic energy distributions. The integral length scale calculated from the PIV data is between 6 and 10 mm and the strain rate is estimated to be within 1000 sÕ1 in most areas of the measurement plane.

Circular scan Spectral-Domain Optic Coherence Tomography imaging (SD-OCT) is one of the best tools for diagnosis of retinal diseases. This technique provides more comprehensive detail of the retinal morphology and layers around the optic disc nerve head (ONH). Since manual labelling of the retinal layers can be tedious and time consuming, accurate and robust automated segmentation methods are needed to provide the thickness evaluation of these layers in retinal disorder assessments such as glaucoma. The proposed method serves this purpose by performing the segmentation of retinal layers boundaries in circular SD-OCT scans acquired around the ONH. The layers are detected by adapting a graph cut segmentation technique that includes a kernel-induced space and a continuous multiplier based max-flow algorithm. Results from scan images acquired with Spectralis (Heidelberg Engineering, Germany) prove that the proposed method is robust and efficient in detecting the retinal layers boundaries in images. With a mean root-mean-square error (RMSE) of 0.0835 ± 0.0495 and an average Dice coefficient of 0.9468 ± 0.0705 pixels for the retinal nerve fibre layer thickness, the proposed method demonstrated effective agreement with manual annotations.

0.16AE1.9 vs -0.12AE2.2 m/s; PZ0.4), or any other haemodynamic variable relative to control at six or 12 months (all P > 0.05). Conclusions: Despite many observational studies to suggest that vitamin D supplementation could be a useful therapy for improving aortic stiffness and associated haemodynamic indices, 12-months intervention yielded no improvement in older people with vitamin D deficiency. These results do not support use of vitamin D supplementation to improve cardiovascular health in this patient population. 3.5Beta-blockers are effective in reducing peripheral blood pressure (pBP), but less effective than other drugs in reducing central blood pressure (cBP). It is controversial whether vasodilating (VB) beta-blockers may be more effective in reducing cBP compared to non-vasodilating (NVB) beta-blockers. Methods: a meta-analysis was conducted by selecting randomized trials exploring the effect of beta-blockers on cBP. Twenty-two studies were selected. Comparisons were made between 33 trial arms (NVBZ22,VBZ11). In a random-effect meta-regression model, the following covariates were introduced: treatment (0Zbaseline, 1Ztreatment), drug class (VB vs NVB), interaction term: (treatment x drug class), mean age, study duration, study design, treatment-induced heart rate changes. Results: 1225 subjects (NVBZ908, VBZ317) were included in the analysis. Mean pSBP was 147 mmHg for NVB and 148 mmHg for VB at baseline, and 133 mmHg for NVB and 134 mmHg for VB after treatment. The difference between pSBP and cSBP at baseline (pSBP -cSBP) was 12.9 mmHg for NVB and 13.4 mmHg for VB. Treatment with either VB or NVB determined a reduction of the above difference to 8.6 mmHg for NVB and 11.3 mmHg for VB (both p<0.01). In the final model, the effect of drug class on the difference between pSBP and cSBP (after treatment -baseline) was not significantly smaller for VB (-2.1 mmHg) than for NVB (-4.3 mmHg; pZ 0.09). Conclusions: VB have a marginally, although not significantly, less unfavourable effects on cSBP than NVB. The blood pressure-lowering effect of betablockers is more pronounced for pSBP than for cSBP. GENE EXPRESSION ANALYSIS IDENTIFY GENES ASSOCIATED WITH ARTERIAL STIFFNESS AND CAROTID DIAMETER IN THE TWINS UK COHORT