Observations of the Vortex Ring State

This paper considers the vortex ring state, a flow condition usually associated with the descent of a rotor into its own wake. The phenomenon is investigated through experiments on simple rotor systems, and a comparison is then made with observations of a flow generated by a specially designed open core, annular jet that generates a mean flow velocity profile similar to the mean flow in a rotor wake in hover. In an experimentally simulated descent, the jet flow generates a flow state that shares many features of the rotor vortex ring state

Low-dimensional Characterization and Control of Bluff-body Wakes. Report 0006

This report is a summary of research conducted for the EPSRC on contract GR/L/59030— “Low-dimensional characterization and control of bluff-body wakes”. The motivation for the work was to investigate active control schemes for stabilizing the low-Reynolds number bluff-body wake, which is an archetypal unstable flow exhibiting self-sustained flow oscillations as a result of global flow instability. Control of bluff-body wake oscillations is of use in drag reduction, noise suppression and prevention of flow induced structural oscillations. Moreover, suppression of closely related unstable flows, such as growth of a dynamic stall vortex on a pitching helicopter blade, may be possible using a similar strategy. To this end, a numerical model of an unstable bluff-body flow was developed and validated by comparison with published literature. Various control strategies involving low-dimensional models of the flow and combinations of distributed sensors and actuators in the near and far wake were investigated. The control results of this study are unique, in that successful control of the flow has been demonstrated further away from criticality than by any other scheme. These results provide a base for continued research in this area and in other related flows (for instance control of helicopter dynamic stall) and has contributed to a publication [1] and several others in preparation

Prevention of folate deficiency by food fortification

Red cell folate levels were measured for 6 weeks in an index member and the oldest member of each of 6 families who had been given folic acid-fortified maize meal for use in the home. Five of the index subjects were pregnant and one was lactating. The amount of folic acid added to the maize was calculated so that each adult would receive 500 /Lg folic acid daily. In the index subjects of 5 of the 6 families studied, red cell folate levels rose significantly. The changes in red cell folate levels suggest that pregnant women consume more maize meal than elderly subjects. This possibility would tend to increase the margin of safety when folic acid-fortified foods are consumed by populations in which vitamin B12 deficient megaloblastic anaemia is found.S. Afr. Med. J., 48, 1763 (1974)

Analysis of travelling waves associated with the modelling of aerosolised skin grafts

A previous model developed by the authors investigates the growth patterns of keratinocyte cell colonies after they have been applied to a burn site using a spray technique. In this paper, we investigate a simplified one-dimensional version of the model. This model yields travelling wave solutions and we analyse the behaviour of the travelling waves. Approximations for the rate of healing and maximum values for both the active healing and the healed cell densities are obtained

Expression of Lamin A/C in early-stage breast cancer and its prognostic value

Purpose: Lamins A/C, a major component of the nuclear lamina, plays key roles in maintaining nuclear integrity, regulation of gene expression, cell proliferation and apoptosis. Reduced lamin A/C expression in cancer has been reported to be a sign of poor prognosis. However, its clinical significance in breast cancer remains to be defined. This study aimed to evaluate expression and prognostic significance of lamin A/C in early-stage breast cancer.Methods: Using immunohistochemical staining of tissue microarrays, expression of lamin A/C was evaluated in a large well-characterised series of early-stage operable breast cancer (n=938) obtained from Nottingham Primary Breast Carcinoma Series. Association of lamin A/C expression with clinicopathological parameters and outcome was evaluated.Results: Positive expression rate of lamin A/C in breast cancer was 42.2% (n=398). Reduced/loss of expression of lamin A/C was significantly associated with high histological grade (p [less than] 0.001), larger tumour size (p=0.004), poor Nottingham Prognostic Index (NPI) score (p [less than] 0.001), lymphovascular invasion (p=0.014) and development of distant metastasis (p=0.027). Survival analysis showed that reduced/loss of expression of lamin A/C was significantly associated with shorter breast cancer specific survival (p=0.008).Conclusion: This study suggests lamin A/C plays a role in breast cancer and loss of its expression is associated with variables of poor prognosis and shorter outcome

Neural responses for evaluating self and mother traits in adolescence depend on mother-adolescent relationships

An important task in adolescence is to achieve autonomy while preserving a positive relationship with parents. Previous fMRI studies showed largely overlapping activation in medial prefrontal cortex (mPFC) for evaluating self and close-other traits but separable activation for self and non-close other. Possibly, more similar mPFC activation ref lects closeness or warmth in relationships. We investigated neural indicators of the mother–adolescent relationship in adolescents between 11 and 21 years (N = 143). Mother–adolescent relationship was measured using (i) mothers’ and adolescents’ trait evaluations about each other, (ii) observations of warmth, negativity and emotional support in mother–adolescent conversation and (iii) similarity in adolescents’ neural activation for evaluating self vs mother traits. Results showed relatively more similar mPFC activation in adolescents who evaluated their mothers’ traits more positively, suggesting that this is possibly a neural indicator of mother–adolescent relationship quality. Furthermore, mid-adolescence was characterized by more negative mother–adolescent interaction compared to early and late adolescence. This effect co-occurred with mid-adolescent peaks in dorsal striatum, dorsal anterior cingulate cortex and superior temporal sulcus activation in evaluating traits of self vs mother. These results suggest more negative relationships and stronger self-focus in mid-adolescenc

Inadequacy of protein intake in older UK adults

The current dietary recommendation for protein intake in the UK is 0.75 g/kg/day, however, this population-wide recommendation does not necessarily reflect altered requirements for older adults to maintain muscle protein synthesis, nor does it encompass the potential impact of intake timing. Optimal muscle protein synthesis in older adults requires both higher intake requirements and a distribution of protein intake above a 25 g threshold, three times across the day. This study aimed to describe the protein intake of older adults in a UK region and compare the results to recommendations. The study re-assessed two existing datasets with rich diet information for older adults in the South Yorkshire area. Data were extracted from food diaries of 256 adults aged between 65 and 89 years old (mean ± SD 72.4 ± 5.3 years). Quantity and timing of intake were coded using Nutritics software and compared to recommendations. The relationship between body mass index (BMI), age, and protein intake was explored. Fewer than 50% of the participants met current UK recommendations (0.75 g/kg/day) and fewer than 15% met the ESPEN 1.2 g/kg/day age-specific recommendation. Only one participant met the 25 g/meal recommendation across three meals. These findings suggest that the older adult population is not achieving recommendations to maintain muscle protein synthesis. Nonetheless it identifies several straightforward opportunities for improvement, notably elevation of morning intake

Combining clustering and classification ensembles: A novel pipeline to identify breast cancer profiles

Breast Cancer is one of the most common causes of cancer death in women, representing a very complex disease with varied molecular alterations. To assist breast cancer prognosis, the classification of patients into biological groups is of great significance for treatment strategies. Recent studies have used an ensemble of multiple clustering algorithms to elucidate the most characteristic biological groups of breast cancer. However, the combination of various clustering methods resulted in a number of patients remaining unclustered. Therefore, a framework still needs to be developed which can assign as many unclustered (i.e. biologically diverse) patients to one of the identified groups in order to improve classification. Therefore, in this paper we develop a novel classification framework which introduces a new ensemble classification stage after the ensemble clustering stage to target the unclustered patients. Thus, a step-by-step pipeline is introduced which couples ensemble clustering with ensemble classification for the identification of core groups, data distribution in them and improvement in final classification results by targeting the unclustered data. The proposed pipeline is employed on a novel real world breast cancer dataset and subsequently its robustness and stability are examined by testing it on standard datasets. The results show that by using the presented framework, an improved classification is obtained. Finally, the results have been verified using statistical tests, visualisation techniques, cluster quality assessment and interpretation from clinical experts

The effect of a barnacle-shaped excrescence on the hydrodynamic performance of a tidal turbine blade section

Efficient tidal turbine designs rely upon the hydrodynamic performance of the turbine blade sections. A significant consideration for the likely power generation capacity of a tidal turbine is the effect of biofouling on the blade performance. A turbine blade surface is susceptible to large scale macrofouling, mainly from encrusters, such as barnacles and molluscs, colonising the developing surface. This paper considers the case of when a barnacle attaches to the upper (suction) surface of the blade section. Results of experiments to investigate the unsteady flow characteristics of the blade section are presented, and the modification of the hydrodynamic performance coefficients due to the presence of a barnacle is evaluated. The barnacle has no significant effect upon the lift in steady flow and unsteady flow, but there is a very large increase in the drag. Dependent upon the degree of barnacle encrustation, the effect on a turbine blade drag may be significant and lead to a degradation of a turbine predicted performance

The Effective Action For Brane Localized Gauge Fields

The low energy effective action including gauge field degrees of freedom on a non-BPS p=2 brane embedded in a N=1, D=4 target superspace is obtained through the method of nonlinear realizations of the associated super-Poincare symmetries. The invariant interactions of the gauge fields and the brane excitation modes corresponding to the Nambu-Goldstone degrees of freedom resulting from the broken space translational symmetry and the target space supersymmetries are determined. Brane localized matter field interactions with the gauge fields are obtained through the construction of the combined gauge and super-Poincare covariant derivatives for the matter fields.Comment: 12 pages, no figure