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Search Results: 1 - 10 of 11396 matches for " Frank Sullivan "
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How much does pre-trial testing influence complex intervention trials and would more testing make any difference? An email survey
Shaun Treweek, Frank Sullivan
BMC Medical Research Methodology , 2006, DOI: 10.1186/1471-2288-6-28
Abstract: Email survey of the authors of complex intervention trials published in seven major journals in 2004.72% (50/69) of eligible authors replied. Eight authors did not consider their interventions to be complex. The majority of respondents' complex interventions were tested (34/42): some extensively. Conversely, only 17 of the 34 published reports describing these trials mention testing. Two-thirds (22/34) of those testing their interventions did not believe that more or different testing would have produced a more effective intervention. 31% (13/42) of all authors did believe further testing would have led to improvements. Five respondents mentioned a lack of funding as a reason for not doing more testing.Complex interventions are generally tested prior to their evaluation in a full-scale trial, although the amount of testing varies. Testing is often not described in trial reports, which makes it hard to judge whether a trial result could be improved with a better intervention, or whether further work with a different intervention is required.In 2000 the UK Medical Research Council published a structure for evaluating complex interventions, which proposed that interventions should be modelled and then tested prior to a full-scale trial [1]. The pre-trial work could be expected to provide a more realistic estimate of the likely effect of the intervention and inform decisions regarding intervention design and delivery. In principle, such work may help to avoid wasting resources evaluating ineffective interventions because rigorous development and testing will reject poor interventions and unfeasible trials before they reach full-scale evaluation [2,3].The aim of the current study was twofold. Firstly, we wanted to survey the estimates of treatment effect and recruitment given in trial reports and compare them with those actually achieved, together with any mention of piloting or testing. Secondly, we wanted to ask the authors of these trial reports whether testing did in
Sustainability and the Astrobiological Perspective: Framing Human Futures in a Planetary Context
Adam Frank,Woodruff Sullivan
Physics , 2013,
Abstract: We explore how questions related to developing a sustainable human civilization can be cast in terms of astrobiology. In particular we show how ongoing astrobiological studies of the coupled relationship between life, planets and their co-evolution can inform new perspectives and direct new studies in sustainability science. Using the Drake Equation as a vehicle to explore the gamut of astrobiology, we focus on its most import factor for sustainability: the mean lifetime of an ensemble of Species with Energy-Intensive Technology (SWEIT). We then cast the problem into the language of dynamical system theory and introduce the concept of a trajectory bundle for SWEIT evolution and discuss how astrobiological results usefully inform the creation of dynamical equations, their constraints and initial conditions. Three specific examples of how astrobiological considerations can be folded into discussions of sustainability are discussed: (1) concepts of planetary habitability, (2) mass extinctions and their possible relation to the current, so-called Anthropocene epoch, and (3) today's changes in atmospheric chemisty (and the climate change it entails) in the context of pervious epochs of biosphere-driven atmospheric and climate alteration (i.e. the Great Oxidation Event).
A New Empirical Constraint on the Prevalence of Technological Species in the Universe
Adam Frank,W. T. Sullivan III
Physics , 2015,
Abstract: In this paper we address the cosmic frequency of technological species. Recent advances in exoplanet studies provide strong constraints on all astrophysical terms in the Drake Equation. Using these and modifying the form and intent of the Drake equation we show that we can set a firm lower bound on the probability that one or more additional technological species have evolved anywhere and at any time in the history of the observable Universe. We find that as long as the probability that a habitable zone planet develops a technological species is larger than ~$10^{-24}$, then humanity is not the only time technological intelligence has evolved. This constraint has important scientific and philosophical consequences.
When Soap Bubbles Collide
Colin Adams,Frank Morgan,John M Sullivan
Mathematics , 2004,
Abstract: Can you fill R^n with a froth of "soap bubbles" that meet at most n at a time? Not if they have bounded diameter, as follows from Lebesgue's Covering Theorem. We provide some related results and conjectures.
Malignant Phyllodes Tumour with Liposarcomatous Differentiation, Invasive Tubular Carcinoma, and Ductal and Lobular Carcinoma In Situ: Case Report and Review of the Literature
Mardiana Abdul Aziz,Frank Sullivan,Michael J. Kerin,Grace Callagy
Pathology Research International , 2010, DOI: 10.4061/2010/501274
Abstract: A 43-year-old woman presented with a right breast lump that had enlarged over 5 months. She had chemoradiotherapy for non-Hodgkin’s lymphoma in 1989. Histology revealed a malignant phyllodes tumour (PT) with liposarcomatous differentiation and ductal carcinoma in situ (DCIS) within the tumour with invasive tubular carcinoma, DCIS, and lobular carcinoma in situ in the surrounding breast. She had surgery and adjuvant radiotherapy. One year follow-up showed no recurrence or metastatic disease. Liposarcomatous differentiation is uncommon in PTs, and coexisting carcinoma is rare with 38 cases in 31 reports in the literature. Carcinoma is reported in malignant ( ), benign ( ) and in borderline PTs ( ) with invasive carcinoma ( ) and pure in situ carcinoma ( ) recorded in equal frequency. Carcinoma is more commonly found within the confines of benign PTs; whereas it is more often found surrounding the PT or in the contralateral breast in malignant PTs. Previous radiotherapy treatment is reported in only two cases. The aetiology of co-existing carcinoma is unclear but the rarity of previous radiotherapy treatment suggests that it is incidental. This case highlights the diverse pathology that can occur with PTs, which should be considered when evaluating pathology specimens as they may impact on patient management. 1. Introduction Phyllodes tumors (PTs) of the breast are uncommon biphasic fibroepithelial neoplasms that account for <1% of all breast tumours. Most PTs are benign and carry a risk of local recurrence whereas malignant PTs have a 13% risk of haematogenous metastasis [1].The distinction between benign, borderline and malignant PT is based on the assessment of a number of histological features including infiltrative margin, stromal overgrowth, stromal atypia, cellularity, and mitotic activity.However,while histological features are helpful, they are not accurate predictors of tumour behavior, and no single parameter is reliable in all cases [2]. PTs are believed to arise from intralobular or periductal stroma and may arise de novo or from pre-existing fibroadenomas [2]. Up to 30% of PTs show malignant transformation, most often in the form of malignant transformation of the stroma, which usually shows fibrosarcomatous differentiation and rarely heterologous sarcomatous elements. Malignant transformation of epithelial elements is very rare with only 38 cases reported in the literature. We present a case of a malignant PT that contained heterologous liposarcomatous stromal differentiation and exhibited a range of epithelial pathology. Ductal carcinoma in
Recruitment and retention in a multicentre randomised controlled trial in Bell's palsy: A case study
Brian McKinstry, Victoria Hammersley, Fergus Daly, Frank Sullivan
BMC Medical Research Methodology , 2007, DOI: 10.1186/1471-2288-7-15
Abstract: Bell's palsy, an acute unilateral paralysis of the facial nerve is just such a relatively rare condition. In this case study we describe the organisational issues presented in setting up a large randomised controlled trial of the management of Bell's palsy across primary and secondary care in Scotland and how we managed to successfully recruit and retain patients presenting in the community.Where possible we used existing evidence on recruitment strategies to maximise recruitment and retention. We consider that the key issues in the success of this study were; the fact that the research was seen as clinically important by the clinicians who had initial responsibility for recruitment; employing an experienced trial co-ordinator and dedicated researchers willing to recruit participants seven days per week and to visit them at home at a time convenient to them, hence reducing missed patients and ensuring they were retained in the study; national visibility and repeated publicity at a local level delivered by locally based principal investigators well known to their primary care community; encouraging recruitment by payment to practices and reducing the workload of the referring doctors by providing immediate access to specialist care; good collaboration between primary and secondary care and basing local investigators in the otolarnygology trial centresAlthough the recruitment rate did not meet our initial expectations, enhanced retention meant that we exceeded our planned target of recruiting 550 patients within the planned time-scale.While difficult, recruitment to and retention within multi-centre trials from primary care can be successfully achieved through the application of the best available evidence, establishing good relationships with practices, minimising the workload of those involved in recruitment and offering enhanced care to all participants. Primary care trialists should describe their experiences of the methods used to persuade patients to participate
Risky sexual behaviours of high-school pupils in an era of HIV and AIDS
S Frank, T Esterhuizen, CC Jinabhai, K Sullivan, M Taylor
South African Medical Journal , 2008,
Abstract: Objective. To identify risky sexual behaviours and demographic factors that place high-school pupils at risk of HIV and AIDS. Methods. A cross-sectional study was undertaken to explore factors influencing the sexual behaviour of high-school pupils (mean age 15.4 years; SD 1.11). Structured self-reported questionnaires were completed by all grade 10 pupils (N=805) at all the Wentworth, Durban, public high schools. Results. Significant gender differences in sexual practices were reported, such as males being more likely to engage in sexual activity than females (OR 4.92; p<0.001). More males (24.8%) initiated sex before age 12, compared with more females (30%) who initiated sex between 16 to 20 years of age (p<0.001). Significantly more males preferred older partners than females (p=0.002), more females were forced to have sex than males (p =0.009), and more males used alcohol on the last occasion of sex than females (p=0.04). Religious affiliation and parental supervision were found to have a significant effect on sexual activity among pupils. Conclusions. High-school pupils are at high risk of HIV and AIDS, yet they continue to engage in risky sexual behaviours. Preventive efforts therefore need to be aggressively up-scaled and redirected towards specific risky practices, taking gender differences into account. Contextual factors such as religious norms and parental supervision also require greater attention. Risky sexual behaviours are reflective of a broader crisis in society. South African Medical Journal Vol. 98 (5) 2008 pp.394-398.
Effect of garlic on blood pressure: A systematic review and meta-analysis
Karin Ried, Oliver R Frank, Nigel P Stocks, Peter Fakler, Thomas Sullivan
BMC Cardiovascular Disorders , 2008, DOI: 10.1186/1471-2261-8-13
Abstract: We searched the Medline and Embase databases for studies published between 1955 and October 2007. Randomised controlled trials with true placebo groups, using garlic-only preparations, and reporting mean systolic and/or diastolic blood pressure (SBP/DBP) and standard deviations were included in the meta-analysis. We also conducted subgroup meta-analysis by baseline blood pressure (hypertensive/normotensive), for the first time. Meta-regression analysis was performed to test the associations between blood pressure outcomes and duration of treatment, dosage, and blood pressure at start of treatment.Eleven of 25 studies included in the systematic review were suitable for meta-analysis. Meta-analysis of all studies showed a mean decrease of 4.6 ± 2.8 mm Hg for SBP in the garlic group compared to placebo (n = 10; p = 0.001), while the mean decrease in the hypertensive subgroup was 8.4 ± 2.8 mm Hg for SBP (n = 4; p < 0.001), and 7.3 ± 1.5 mm Hg for DBP (n = 3; p < 0.001). Regression analysis revealed a significant association between blood pressure at the start of the intervention and the level of blood pressure reduction (SBP: R = 0.057; p = 0.03; DBP: R = -0.315; p = 0.02).Our meta-analysis suggests that garlic preparations are superior to placebo in reducing blood pressure in individuals with hypertension.Hypertension (systolic blood pressure (SBP) ≥ 140 mm Hg; diastolic blood pressure (DBP) ≥ 90 mm Hg) is a known risk factor for cardiovascular morbidity and mortality, affecting an estimated 1 billion individuals worldwide [1]. Recently updated guidelines for the treatment of high blood pressure stress the importance of preventive strategies, and recommend extending the management of blood pressure to include pre-hypertensive individuals (SBP 120–139/DBP 80–89 mm Hg) [1]. Primary management should include relevant lifestyle modifications such as increased exercise, weight loss and dietary changes which could incorporate dietary supplementation.Garlic (Allium sativum) h
Reduction in podocyte density as a pathologic feature in early diabetic nephropathy in rodents: Prevention by lipoic acid treatment
Brian Siu, Jharna Saha, William E Smoyer, Kelli A Sullivan, Frank C Brosius
BMC Nephrology , 2006, DOI: 10.1186/1471-2369-7-6
Abstract: The number of podocytes per glomerular section and the podocyte density in glomeruli from rats and mice with streptozotocin (STZ)-diabetes mellitus was determined at several time points based on detection of the glomerular podocyte specific antigens, WT-1 and GLEPP1. The effect of insulin administration or treatment with the antioxidant, α-lipoic acid, on podocyte number was assessed.Experimental diabetes resulted in a rapid decline in apparent podocyte number and podocyte density. A significant reduction in podocytes/glomerular cross-section was found in STZ diabetes in rats at 2 weeks (14%), 6 weeks (18%) and 8 weeks (34%) following STZ injection. Similar declines in apparent podocyte number were found in STZ diabetes in C57BL/6 mice at 2 weeks, but not at 3 days after injection. Treatment with α-lipoic acid substantially prevented podocyte loss in diabetic rats but treatment with insulin had only a modest effect.STZ diabetes results in reduction in apparent podocyte number and in podocyte density within 2 weeks after onset of hyperglycemia. Prevention of these effects with antioxidant therapy suggests that this early reduction in podocyte density is due in part to increased levels of reactive oxygen species as well as hyperglycemia.The clinical hallmarks of diabetic nephropathy include progressive albuminuria followed by a gradual decline in renal function concluding, after 5–15 years, with end-stage renal disease. Glomerular basement thickening and mesangial expansion, due to accumulation of extracellular matrix proteins, have been identified as pathological precursors of these clinical changes [1]. In the last few years, several reports have suggested that loss of glomerular epithelial cells, or podocytes, precedes and predicts the onset of clinical nephropathy and may be an early pathological manifestation of diabetic nephropathy [2-4]. Moreover, it has been postulated that the loss of podocytes could be pathogenically important in leading to glomerular scarri
Does chocolate reduce blood pressure? A meta-analysis
Karin Ried, Thomas Sullivan, Peter Fakler, Oliver R Frank, Nigel P Stocks
BMC Medicine , 2010, DOI: 10.1186/1741-7015-8-39
Abstract: We searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP) for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive). Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P < 0.05.Fifteen trial arms of 13 assessed studies met the inclusion criteria. Pooled meta-analysis of all trials revealed a significant blood pressure-reducing effect of cocoa-chocolate compared with control (mean BP change ± SE: SBP: -3.2 ± 1.9 mmHg, P = 0.001; DBP: -2.0 ± 1.3 mmHg, P = 0.003). However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 ± 3.0 mmHg; P = 0.0009; DBP: -2.7 ± 2.2 mm Hg, P = 0.01), while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 ± 2.3 mmHg, P = 0.17; DBP: -1.3 ± 1.6 mmHg, P = 0.12). Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30 mg to 1000 mg in the active treatment groups, and interventions ran for 2 to 18 weeks. Meta-regression analysis found study design and type of control to be borderline significant but possibly indirect predictors for blood pressure outcome.Our meta-analysis suggests that dark chocolate is superior to placebo in reducing systolic hypertension or diastolic prehypertension. Flavanol-rich chocolate did not significantly reduce mean blood pressure below 140 mmHg systolic or 80 mmHg diastolic.Flavanol-rich chocolate and cocoa products hav
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