Experimental validation of the distributed drag method for simulating large marine current turbine arrays using porous fences

Marine current energy conversion can provide significant electrical power from resource-rich sites. However since no large marine current turbine arrays currently exist, validation of methods for simulating energy extraction relies upon scaled down laboratory experiments. We present results from an experiment using porous fences spanning the width of a recirculating flume to simulate flow through large, regular, multi-row marine current turbine arrays. Measurements of fence drag, free surface elevation drop and velocity distribution were obtained to validate a method for parameterising array drag in the distributed drag approach, which is typically implemented in regional scale models. The effect of array density was also investigated by varying the spacing between fences. Two different inflow conditions were used; the first used the flume bed in its natural state, whilst the second used roughness strips on the flume bed to significantly enhance ambient turbulence intensity to levels similar to those recorded at tidal sites. For realistic array densities (<0.07), a depth averaged formulation of effective array drag coefficient agreed within 10% of that derived from experimental results for both inflow conditions. The validity of the distributed drag approach was shown to be dependent on longitudinal row spacing between porous fences and ambient turbulence intensity, two features that determine the level of wake recovery downstream of each porous fence. Finally a force balance analysis quantified the change in bed drag as a result of the presence of porous fence arrays. Adding arrays to the flow gave an increase in bed drag coefficient of up to 95% which was 20% of the total added bed and array drag coefficient. Results have implications for regional scale hydrodynamic modelling, where array layout along with site specific characteristics such as turbulence intensity and bed profile determine the validity of the distributed drag approach for simulating energy extraction

Experimental validation of the distributed drag method for simulating large marine current turbine arrays using porous fences

Marine current energy conversion can provide significant electrical power from resource-rich sites. However since no large marine current turbine arrays currently exist, validation of methods for simulating energy extraction relies upon scaled down laboratory experiments. We present results from an experiment using porous fences spanning the width of a recirculating flume to simulate flow through large, regular, multi-row marine current turbine arrays. Measurements of fence drag, free surface elevation drop and velocity distribution were obtained to validate a method for parameterising array drag in the distributed drag approach, which is typically implemented in regional scale models. The effect of array density was also investigated by varying the spacing between fences. Two different inflow conditions were used; the first used the flume bed in its natural state, whilst the second used roughness strips on the flume bed to significantly enhance ambient turbulence intensity to levels similar to those recorded at tidal sites. For realistic array densities (<0.07), a depth averaged formulation of effective array drag coefficient agreed within 10% of that derived from experimental results for both inflow conditions. The validity of the distributed drag approach was shown to be dependent on longitudinal row spacing between porous fences and ambient turbulence intensity, two features that determine the level of wake recovery downstream of each porous fence. Finally a force balance analysis quantified the change in bed drag as a result of the presence of porous fence arrays. Adding arrays to the flow gave an increase in bed drag coefficient of up to 95% which was 20% of the total added bed and array drag coefficient. Results have implications for regional scale hydrodynamic modelling, where array layout along with site specific characteristics such as turbulence intensity and bed profile determine the validity of the distributed drag approach for simulating energy extraction

Assessment of the energy extraction potential at tidal sites around the Channel Islands

Tidal flows around the Channel Islands contain a significant energy resource that if harnessed could provide electrical power to the Channel Islands, the UK and France. We have developed a new 2D hydrodynamic model of the English Channel which gives an improvement to the temporal and spatial resolution of the ambient flow in comparison with previous regional scale resource assessments. The ambient flow was characterised to identify suitable sites, resulting in a reduction in total development area of up to 80% compared with previous studies. Estimates for upper bound energy extraction confirm that Alderney Race contains the majority of the Channel Islands resource, giving a maximum potential of 5.1 GW, which exceeds a previous estimate for the Pentland Firth by 35%. This is followed by Casquets (0.47 GW) and then Big Roussel (0.24 GW). Our work shows that energy extraction at Alderney Race has a constructive impact on the resource at Casquets, and that the sensitivity to added drag at each site with respect to energy extraction is highly dependent on bathymetry and the proximity of coastlines. These results have implications for the overall resource development within the Channel Islands, where regulation is needed to account for site-site interaction

Anthropometric indices of Gambian children after one or three annual rounds of mass drug administration with azithromycin for trachoma control.

BACKGROUND: Mass drug administration (MDA) with azithromycin, carried out for the control of blinding trachoma, has been linked to reduced mortality in children. While the mechanism behind this reduction is unclear, it may be due, in part, to improved nutritional status via a potential reduction in the community burden of infectious disease. To determine whether MDA with azithromycin improves anthropometric indices at the community level, we measured the heights and weights of children aged 1 to 4 years in communities where one (single MDA arm) or three annual rounds (annual MDA arm) of azithromycin had been distributed. METHODS: Data collection took place three years after treatment in the single MDA arm and one year after the final round of treatment in the annual MDA arm. Mean height-for-age, weight-for-age and weight-for-height z scores were compared between treatment arms. RESULTS: No significant differences in mean height-for-age, weight-for-age or weight-for-height z scores were found between the annual MDA and single MDA arms, nor was there a significant reduction in prevalence of stunting, wasting or underweight between arms. CONCLUSIONS: Our data do not provide evidence that community MDA with azithromycin improved anthropometric outcomes of children in The Gambia. This may suggest reductions in mortality associated with azithromycin MDA are due to a mechanism other than improved nutritional status

Neuroprotection in a Novel Mouse Model of Multiple Sclerosis

The authors acknowledge the support of the Barts and the London Charity, the Multiple Sclerosis Society of Great Britain and Northern Ireland, the National Multiple Sclerosis Society, USA, notably the National Centre for the Replacement, Refinement & Reduction of Animals in Research, and the Wellcome Trust (grant no. 092539 to ZA). The siRNA was provided by Quark Pharmaceuticals. The funders and Quark Pharmaceuticals had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Critical research gaps and translational priorities for the successful prevention and treatment of breast cancer

INTRODUCTION Breast cancer remains a significant scientific, clinical and societal challenge. This gap analysis has reviewed and critically assessed enduring issues and new challenges emerging from recent research, and proposes strategies for translating solutions into practice. METHODS More than 100 internationally recognised specialist breast cancer scientists, clinicians and healthcare professionals collaborated to address nine thematic areas: genetics, epigenetics and epidemiology; molecular pathology and cell biology; hormonal influences and endocrine therapy; imaging, detection and screening; current/novel therapies and biomarkers; drug resistance; metastasis, angiogenesis, circulating tumour cells, cancer 'stem' cells; risk and prevention; living with and managing breast cancer and its treatment. The groups developed summary papers through an iterative process which, following further appraisal from experts and patients, were melded into this summary account. RESULTS The 10 major gaps identified were: (1) understanding the functions and contextual interactions of genetic and epigenetic changes in normal breast development and during malignant transformation; (2) how to implement sustainable lifestyle changes (diet, exercise and weight) and chemopreventive strategies; (3) the need for tailored screening approaches including clinically actionable tests; (4) enhancing knowledge of molecular drivers behind breast cancer subtypes, progression and metastasis; (5) understanding the molecular mechanisms of tumour heterogeneity, dormancy, de novo or acquired resistance and how to target key nodes in these dynamic processes; (6) developing validated markers for chemosensitivity and radiosensitivity; (7) understanding the optimal duration, sequencing and rational combinations of treatment for improved personalised therapy; (8) validating multimodality imaging biomarkers for minimally invasive diagnosis and monitoring of responses in primary and metastatic disease; (9) developing interventions and support to improve the survivorship experience; (10) a continuing need for clinical material for translational research derived from normal breast, blood, primary, relapsed, metastatic and drug-resistant cancers with expert bioinformatics support to maximise its utility. The proposed infrastructural enablers include enhanced resources to support clinically relevant in vitro and in vivo tumour models; improved access to appropriate, fully annotated clinical samples; extended biomarker discovery, validation and standardisation; and facilitated cross-discipline working. CONCLUSIONS With resources to conduct further high-quality targeted research focusing on the gaps identified, increased knowledge translating into improved clinical care should be achievable within five years

Assays to Detect β-Tubulin Codon 200 Polymorphism in Trichuris trichiura and Ascaris lumbricoides

The soil-transmitted helminths Ascaris lumbricoides and Trichuris trichiura are gastrointestinal nematodes causing many disabilities in tropical parts of the developing world. Control programs, such as “The Focussing Resources on Effective School Health” (FRESH) Partnership, have been implemented to remove human soil-transmitted nematodes through large-scale use of benzimidazole anthelmintic drugs for school-aged children in developing countries. The benzimidazole drugs albendazole and mebendazole are commonly used as a single annual treatment in areas where the burden is high. In veterinary nematodes, repeated use of these anthelmintics has selected for resistant populations. Resistance to benzimidazoles is commonly associated with a single amino acid substitution from phenylalanine to tyrosine in the β-tubulin gene at position 200. In this study, we have developed pyrosequencing assays for codon 200 in A. lumbricoides and T. trichiura to screen for this single nucleotide polymorphism (SNP) in β-tubulin. The 200Tyr SNP was detected at low frequency in T. trichiura from non-treated people from Kenya and at high frequency in T. trichiura from treated people from Panama. The presence of the resistance-associated SNP may play a role in the sometimes low and variable efficacy of benzimidazole anthelmintics against T. trichiura

Electroacupuncture versus Diclofenac in symptomatic treatment of Osteoarthritis of the knee: a randomized controlled trial

BACKGROUND: The purpose of this study was to compare the efficacy of electroacupuncture (EA), diclofenac and their combination in symptomatic treatment of osteoarthritis (OA) of the knee. METHODS: This study was a randomized, single-blind, placebo controlled trial. The 193 out-patients with OA of the knee were randomized into four groups: placebo, diclofenac, EA and combined (diclofenac plus EA). Paracetamol tablets were prescribed as a rescue analgesic during the study. The patients were evaluated after a run-in period of one week (week 0) and again at the end of the study (week 4). The clinical assessments included the amount of paracetamol taken/week, visual analog scale (VAS), Western Ontario and McMaster Universities (WOMAC) OA Index, Lequesne's functional index, 50 feet-walk time, and the orthopedist's and patient's opinion of change. RESULTS: One hundred and eighty six patients completed the study. The improvement of symptoms (reduction in mean changes) in most outcome parameters was greatest in the EA group. The proportions of responders and patients with an overall opinion of "much better" were also greatest in the EA group. The improvement in VAS was significantly different between the EA and placebo group as well as the EA and diclofenac group. The improvement in Lequesne's functional index also differed significantly between the EA and placebo group. In addition, there was a significant improvement in WOMAC pain index between the combined and placebo group. CONCLUSION: EA is significantly more effective than placebo and diclofenac in the symptomatic treatment of OA of the knee in some circumstances. However, the combination of EA and diclofenac treatment was no more effective than EA treatment alone

Systematic review of interventions for children with Fetal Alcohol Spectrum Disorders

<p>Abstract</p> <p>Background</p> <p>Children with Fetal Alcohol Spectrum Disorders (FASD) may have significant neurobehavioural problems persisting into adulthood. Early diagnosis may decrease the risk of adverse life outcomes. However, little is known about effective interventions for children with FASD. Our aim is to conduct a systematic review of the literature to identify and evaluate the evidence for pharmacological and non-pharmacological interventions for children with FASD.</p> <p>Methods</p> <p>We did an electronic search of the Cochrane Library, MEDLINE, EMBASE, PsychINFO, CINAHL and ERIC for clinical studies (Randomized controlled trials (RCT), quasi RCT, controlled trials and pre- and post-intervention studies) which evaluated pharmacological, behavioural, speech therapy, occupational therapy, physiotherapy, psychosocial and educational interventions and early intervention programs. Participants were aged under 18 years with a diagnosis of a FASD. Selection of studies for inclusion and assessment of study quality was undertaken independently by two reviewers. Meta-analysis was not possible due to diversity in the interventions and outcome measures.</p> <p>Results</p> <p>Twelve studies met the inclusion criteria. Methodological weaknesses were common, including small sample sizes; inadequate study design and short term follow up. Pharmacological interventions, evaluated in two studies (both RCT) showed some benefit from stimulant medications. Educational and learning strategies (three RCT) were evaluated in seven studies. There was some evidence to suggest that virtual reality training, cognitive control therapy, language and literacy therapy, mathematics intervention and rehearsal training for memory may be beneficial strategies. Three studies evaluating social communication and behavioural strategies (two RCT) suggested that social skills training may improve social skills and behaviour at home and Attention Process Training may improve attention.</p> <p>Conclusion</p> <p>There is limited good quality evidence for specific interventions for managing FASD, however seven randomized controlled trials that address specific functional deficits of children with FASD are underway or recently completed.</p

Neural Stem/Progenitor Cells from the Adult Human Spinal Cord Are Multipotent and Self-Renewing and Differentiate after Transplantation

Neural stem/progenitor cell (NSPC) transplantation is a promising therapy for spinal cord injury (SCI). However, little is known about NSPC from the adult human spinal cord as a donor source. We demonstrate for the first time that multipotent and self-renewing NSPC can be cultured, passaged and transplanted from the adult human spinal cord of organ transplant donors. Adult human spinal cord NSPC require an adherent substrate for selection and expansion in EGF (epidermal growth factor) and FGF2 (fibroblast growth factor) enriched medium. NSPC as an adherent monolayer can be passaged for at least 9 months and form neurospheres when plated in suspension culture. In EGF/FGF2 culture, NSPC proliferate and primarily express nestin and Sox2, and low levels of markers for differentiating cells. Leukemia inhibitory factor (LIF) promotes NSPC proliferation and significantly enhances GFAP expression in hypoxia. In differentiating conditions in the presence of serum, these NSPC show multipotentiality, expressing markers of neurons, astrocytes, and oligodendrocytes. Dibutyryl cyclic AMP (dbcAMP) significantly enhances neuronal differentiation. We transplanted the multipotent NSPC into SCI rats and show that the xenografts survive, are post-mitotic, and retain the capacity to differentiate into neurons and glia