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Imperial College London is a public research university located in London, United Kingdom. As a former constituent college of the federal University of London, it became fully independent during the commemoration of its centenary on 9 July 2007. Imperial has grown through mergers, including with St Mary's Hospital Medical School , the National Heart and Lung Institute and the Charing Cross and Westminster Medical School . Imperial College Business School was established in 2003 and its building opened by the Queen of England in 2004.Imperial is organised into four main faculties: science, engineering, medicine and business; within the school there are over 40 departments, institutes and research centres. Imperial has around 13,500 students and 3,330 academic and research staff. Imperial's main campus is located in the South Kensington area of London, with additional campuses in Chelsea, Hammersmith, Paddington, Silwood Park, Wye College, and Singapore, making it one of the largest estates of any UK tertiary institution.Imperial is a major centre for biomedical research with the research staff having a total income of £822 million in 2012/13. Imperial is a founding member of the Francis Crick Institute and Imperial College Healthcare. Imperial is a member of the Association of Commonwealth Universities, the European University Association, the Association of MBAs, the G5, the League of European Research Universities, Oak Ridge Associated Universities and the Russell Group. Along with Cambridge and Oxford, Imperial, forms a corner of the "golden triangle" of British universities.Imperial is one of the most selective British universities. Imperial is consistently ranked among the top universities in the world, ranking 2nd in the 2014/15 QS World University Rankings and 9th in the 2014/15 Times Higher Education World University Rankings. In a corporate study carried out by The New York Times, its graduates were one of the most valued globally. Imperial's alumni and faculty include 15 Nobel laureates, 2 Fields Medalists, 70 Fellows of the Royal Society, 82 Fellows of the Royal Academy of Engineering, and 78 Fellows of the Academy of Medical science. Wikipedia.

Birch A.M.,Imperial College London
Biochemical Society Transactions | Year: 2014

Astrocytes were historically classified as supporting cells; however, it is becoming increasingly clear that they actively contribute to neuronal functioning under normal and pathological conditions. As interest in the contribution of neuroinflammation to Alzheimer's disease (AD) progression has grown, manipulating glial cells has become an attractive target for future therapies. Astrocytes have largely been under-represented in studies that assess the role of glia in these processes, despite substantial evidence of astrogliosis in AD. The actual role of astrocytes in AD remains elusive, as they seem to adopt different functions dependent on disease progression and the extent of accompanying parenchymal inflammation. Astrocytes may contribute to the clearance of amyloid β-peptide (Aβ) and restrict the spread of inflammation in the brain. Conversely, they may contribute to neurodegeneration in AD by releasing neurotoxins and neglecting crucial metabolic roles. The present review summarizes current evidence on the multi-faceted functions of astrocytes in AD, highlighting the significant scope available for future therapeutic targets. ©The Authors Journal compilation ©2014 Biochemical Society. Source

Whilst the heritable nature of Type 2 diabetes has been recognized for many years, only in the past two decades have linkage analyses in families and genome-wide association studies in large populations begun to reveal the genetic landscape of the disease in detail. Whilst the former have provided a powerful means of identifying the genes responsible for monogenic forms of the disease, the latter highlight relatively large genomic regions. These often harbour multiple genes, whose relative contribution to exaggerated disease risk is uncertain. In the present study, the approaches that have been used to dissect the role of just a few (TCF7L2, SLC30A8, ADCY5, MTNR1B and CDKAL1) of the ~ 500 genes identified at dozens of implicated loci are described. These are usually selected based on the strength of their effect on disease risk, and predictions as to their likely biological role. Direct determination of the effects of identified polymorphisms on gene expression in disease-relevant tissues, notably the pancreatic islet, are then performed to identify genes whose expression is affected by a particular polymorphism. Subsequent functional analyses then involve perturbing gene expression in vitro in β-cell lines or isolated islets and in vivo in animal models. Although the majority of polymorphisms affect insulin production rather than action, and mainly affect the β cell, effects via other tissues may also contribute, requiring careful consideration in the design and interpretation of experiments in model systems. These considerations illustrate the scale of the task needed to exploit genome-wide association study data for the development of new therapeutic strategies. © 2014 Diabetes UK. Source

Barnes P.J.,Imperial College London
Chemical Immunology and Allergy | Year: 2014

Glucocorticoids are the most effective anti-inflammatory treatment for allergic diseases, and inhaled glucocorticoids have now become the first-line treatment for asthma. Glucocorticoids were discovered in the 1940s as extracts of the adrenal cortex and this was followed by the isolation of adrenocorticotropic hormone (ACTH) from pituitary gland extracts. Cortisone and ACTH were found to be very beneficial in the treatment of rheumatoid arthritis and Kendall, Reichstein and Hench received the Nobel Prize in Physiology and Medicine for this work in 1950. Bordley and colleagues first showed that ACTH was very beneficial in the treatment of allergic diseases in 1949, but the use of systemic glucocorticoids was limited by side effects. Inhaled glucocorticoids were discovered from topical steroids developed for skin inflammation and beclomethasone dipropionate was introduced in 1972, initially in low doses but later in higher doses, and became the standard treatment for persistent asthma. Subsequently, inhaled glucocorticoids were combined with long-acting β2-agonists in combination inhalers for even greater therapeutic benefit. There is now a good understanding of the molecular basis for the anti-inflammatory effects of glucocorticoids in allergic diseases. The search for even safer glucocorticoids based on the dissociation of anti-inflammatory and side effect mechanisms is currently ongoing. © 2014 S. Karger AG, Basel. Source

The last few years have witnessed a revolution in the diagnostic microbiology laboratory with the emergence of matrix assisted laser desorption/ionisation time-offlight mass spectrometry (MALDI- TOF MS) as an indispensible tool in microbial identification. In many laboratories this has superseded biochemical profiling. A mass spectrum is acquired from an unknown microorganism and this proteomic fingerprint is then compared with a database of reference spectra to ascertain the likely genus and species identity. The reproducibility of this method is facilitated by the analysis of continually produced, highly abundant proteins (mainly ribosomal proteins) in the mass range 2000 to 20 000 Da. MALDI- TOF MS is reliable and rapid and has the ability to determine the identity of an isolate from culture in a matter of minutes rather than the hours or days required by more traditional methods. In addition to microbial identification of cultured isolates, work is underway to extend the utility of MALDI- TOF MS to include bacterial identification directly from clinical samples as well as providing timely information regarding antibiotic resistance and typing of different micro-organisms. Source

Clark P.,Imperial College London
Thorax | Year: 2014

Ectodomain shedding is the proteolytic cleavage of cell surface proteins resulting in the loss of the extracellular domains. This mechanism is important in a variety of normal and pathological processes, including growth factor signalling, cell adhesion, inflammation and cell survival. Elevated protease activity in the lungs is a key pathological mechanism in emphysema which could enhance ectodomain shedding in lung cells. Here, the major steps and consequences of ectodomain shedding are reviewed. Source

Young A.H.,Imperial College London
Acta psychiatrica Scandinavica. Supplementum | Year: 2013

This article reviews the characteristics of bipolar disorder and approaches to minimise physical health risks, as well as treatment options, and their influence on patient quality of life (QoL). The content of this article is based on the proceedings of a 1-day standalone symposium in November 2011 exploring how to establish a bipolar clinic within the context of existing services in the UK's National Health Service. Bipolar disorder is a common mental disorder and often under-recognised in patients with major depressive episodes. Patients are largely dependent on family and carers to lead normal lifestyles and have difficulties maintaining relationships. Mental health and physical health are closely linked, with risk factors such as weight gain, metabolic syndrome, smoking and diabetes contributing to cardiovascular disease and early death. Antipsychotics may induce treatment-related comorbidities, thus further contributing to a low QoL of patients. Symptoms of comorbidity or depression are frequently relieved through self-medication and substance abuse, thus increasing patient health and suicide risk. Therefore, regular health monitoring and patient education in risk factor minimisation are required. Early pharmacotherapeutic and psychoeducational interventions are required to improve treatment outcomes, as well as improving patient understanding of ways to minimise comorbidity development. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd. Source

Treat N.D.,Imperial College London | Chabinyc M.L.,University of California at Santa Barbara
Annual Review of Physical Chemistry | Year: 2014

Thin-film solar cells are an important source of renewable energy. The most efficient thin-film solar cells made with organic materials are blends of semiconducting polymers and fullerenes called the bulk heterojunction (BHJ). Efficient BHJs have a nanoscale phase-separated morphology that is formed during solution casting. This article reviews recent work to understand the nature of the phase-separation process resulting in the formation of the domains in polymer-fullerene BHJs. The BHJ is now viewed as a mixture of polymer-rich, fullerene-rich, and mixed polymer-fullerene domains. The formation of this structure can be understood through fundamental knowledge of polymer physics. The implications of this structure for charge transport and charge generation are given. Copyright © 2014 by Annual Reviews. Source

Hoare B.,Humboldt University of Berlin | Tseytlin A.A.,Imperial College London | Tseytlin A.A.,RAS Lebedev Physical Institute
Nuclear Physics B | Year: 2013

The type IIB supergravity AdS3×S3×T4 background with mixed RR and NSNS 3-form fluxes is a near-horizon limit of a non-threshold bound state of D5-D1 and NS5-NS1 branes. The corresponding superstring world-sheet theory is expected to be integrable, opening the possibility of computing its exact spectrum for any values of the coefficient q of the NSNS flux and the string tension. In arXiv:1303.1447 we have found the tree-level S-matrix for the massive BMN excitations in this theory, which turned out to have a simple dependence on q. Here, by analyzing the constraints of symmetry and integrability, we propose an exact massive-sector dispersion relation and the exact S-matrix for this world-sheet theory. The S-matrix generalizes its recent construction in the q=0 case in arXiv:1303.5995. © 2013 Elsevier B.V. Source

Dalakas M.C.,Imperial College London
Current Treatment Options in Neurology | Year: 2010

Polyneuropathies associated with IgM monoclonal gammopathies comprise a distinct entity. In spite of the apparent pathogenicity of the IgM antibodies and the specific immunoreactivity to myelin antigens, the disease has been difficult to treat. This review describes the clinical phenotype, addresses recent data on immunoreactivity of IgM to various nerve antigens, and discusses the latest progress on treatment. Most of these patients present with paresthesias and sensory ataxia followed by a varying degree of sensorimotor deficits. In more than 75% of the patients, the monoclonal IgM recognizes myelin-associated glycoprotein (MAG) and sulfoglucuronyl glycosphingolipid (SGPG), best detected by ELISA, or other peripheral nerve glycolipids. Recent experiments have demonstrated that animals immunized with SGPG develop sensory ataxia, suggesting a pathogenic role for this antigen. Although cladribine, cyclophosphamide with prednisone, and intravenous immunoglobulin have offered transient benefits to some patients, most have remained treatment-resistant. Open label studies and a recent randomized controlled trial indicate that rituximab is emerging as the best agent available, providing long-term benefits to almost half of these patients. Rituximab appears to work by suppressing the IgM as well as the anti-MAG antibodies and by inducing immunoregulatory T cells. Patients with more sensory deficits and higher anti-MAG antibodies are more likely to respond but may require re-treatment after several months. These encouraging results need confirmation with a larger trial. Data on long-term efficacy and immune markers associated with response to therapy or need for re-treatment are still needed. © Springer Science+Business Media, LLC 2010. Source

Jayasena C.N.,Institute of Reproductive and Developmental Biology | Franks S.,Imperial College London
Nature Reviews Endocrinology | Year: 2014

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women. The syndrome is typified by its heterogeneous presentation, which includes hirsutism (a function of hypersecretion of ovarian androgens), menstrual irregularity and infertility (that is due to infrequent or absent ovulation). Furthermore, PCOS predisposes patients to metabolic dysfunction and an increased risk of type 2 diabetes mellitus (T2DM). The aetiology of the syndrome has a major genetic component. Obesity exacerbates the insulin resistance that is a feature of PCOS in many women and amplifies the clinical and biochemical abnormalities. In clinical practice, the choice of investigations to be done depends mainly on the presenting symptoms. The approach to management is likewise dependent on the presenting complaint. Symptoms of androgen excess (hirsutism, acne and alopecia) require cosmetic measures, suppression of ovarian androgen function and anti-androgen therapy, alone or in combination. Ovulation rate is improved by diet and lifestyle intervention in overweight individuals but induction of ovulation by, in the first instance, anti-estrogens is usually required. Monitoring of glucose is important in overweight women and/or those with a family history of T2DM. Metformin is indicated for women with impaired glucose tolerance but whether this drug is otherwise useful in women with PCOS remains debatable. © 2014 Macmillan Publishers Limited. All rights reserved. Source

Griffith E.C.,University of Colorado at Boulder | Tuck A.F.,Imperial College London | Vaida V.,University of Colorado at Boulder
Accounts of Chemical Research | Year: 2012

The prebiotic conversion of simple organic molecules into complex biopolymers necessary for life can only have emerged on a stage set by geophysics. The transition between "prebiotic soup," the diverse mixture of small molecules, and complex, self-replicating organisms requires passing through the bottleneck of fundamental chemistry. In this Account, we examine how water-air interfaces, namely, the surfaces of lakes, oceans, and atmospheric aerosols on ancient Earth, facilitated the emergence of complex structures necessary for life. Aerosols are liquid or solid suspensions in air with a broad, power law size distribution. Collectively, these globally distributed atmospheric particles have an enormous surface area. Organic films at the interface between water and air offer advantages for biomolecular synthesis compared with the bulk and can simultaneously participate in the folding of biopolymers into primitive enclosed structures.We survey the advantages of the water-air interface for prebiotic chemistry in a geophysical context from three points of view. We examine the formation of biopolymers from simple organic precursors and describe the necessity and availability of enclosures. In addition, we provide a statistical mechanical approach to natural selection and emergence of complexity that proposes a link between these molecular mechanisms and macroscopic scales. Very large aerosol populations were ubiquitous on ancient Earth, and the surfaces of lakes, oceans, and atmospheric aerosols would have provided an auspicious environment for the emergence of complex structures necessary for life. These prebiotic reactors would inevitably have incorporated the products of chemistry into their anhydrous, two-dimensional organic films in the three-dimensional fluids of the gaseous atmosphere and the liquid ocean. The untrammeled operation of natural selection on these aerosols provided the likely location where condensation reactions could form biopolymers by elimination of water. The fluctuating exposure of the large, recycling aerosol populations to radiation, pressure, temperature, and humidity over geological time allows complexity to emerge from simple molecular precursors. We propose an approach that connects chemical statistical thermodynamics and the macroscopic world of the planetary ocean and atmosphere. © 2012 American Chemical Society. Source

Pawar S.,Imperial College London
Advances in Ecological Research | Year: 2015

Body size determines key behavioral and life history traits across species, as well as interactions between individuals within and between species. Therefore, variation in sizes of immigrants, by exerting variation in trophic interaction strengths, may drive the trajectory and outcomes of community assembly. Here, I study the effects of size variation in the immigration pool on assembly dynamics and equilibrium distributions of sizes and consumer-resource size-ratios using a general mathematical model. I find that because small sizes both, improve the ability to invade and destabilize the community, invasibility and stability pull body size distributions in opposite directions, favoring an increase in both size and size-ratios during assembly, and ultimately yielding a right-skewed size and a symmetric size-ratio distribution. In many scenarios, the result at equilibrium is a systematic increase in body sizes and size-ratios with trophic level. Thus these patterns in size structure are 'signatures' of dynamically constrained, non-neutral community assembly. I also show that for empirically feasible distributions of body sizes in the immigration pool, immigration bias in body sizes cannot counteract dynamical constraints during assembly and thus signatures emerge consistently. I test the theoretical predictions using data from nine terrestrial and aquatic communities and find strong evidence that natural communities do indeed exhibit such signatures of dynamically constrained assembly. Overall, the results provide new measures to detect general, non-neutral patterns in community assembly dynamics, and show that in general, body size is dominant trait that strongly influences assembly and recovery of natural communities and ecosystems. © 2015 Elsevier Ltd. Source

Need A.C.,Imperial College London | Goldstein D.B.,Duke University
Neuron | Year: 2014

The new GWAS from the Schizophrenia Working Group of the Psychiatric Genomics Consortium (2014) clearly validates a genetic approach to understanding schizophrenia. The challenge now remains to track down the contributing genes and to develop appropriate models to elucidate the biological effects of the contributing variants. © 2014 Elsevier Inc. Source

Sherlock M.,Imperial College London
Physical Review Letters | Year: 2010

A generalized Ohm's law is derived for a system composed of a background magnetohydrodynamic plasma and a lower density relativistic charged-particle distribution. The interpretation of Ohmic electric fields occurring due to force balance breaks down for such a system and instead an approach based on Maxwell's equations along with the particle flux equations is necessary. Three additional terms arise in Ohm's law and each is verified numerically. © 2010 The American Physical Society. Source

McGlashan N.R.,Imperial College London
International Journal of Hydrogen Energy | Year: 2010

Adoption of the hydrogen economy (HE) is one means by which industrial economies can reduce point source CO2 emissions. At its simplest, H2 is generated centrally using a primary energy source to split water; the H2 is then transmitted to end users, thereby 'carrying' energy from the central plant to, say, a motor vehicle. Assuming the primary energy input to drive the system comes from fossil fuels, carbon capture at these plants is required to reduce the specific CO2 emissions of the system to the minimum. However, an additional thermodynamic advantage of the HE is often ignored, as it facilitates a rise in second law efficiency in the utilisation of fossil fuels. The HE can be viewed as an open-loop, chemical looping combustion (CLC) system, with H2 as the oxygen carrier. In CLC systems, entropy recirculation leads to a reduction in the reversible reaction temperature; in the HE this results in a rise in the efficiency of both H2 producing and H2 consuming devices. In consequence, the second law efficiency of internal combustion engines burning H2 is increased for a given peak cycle temperature. For fuel cells, with notionally higher thermal efficiency than internal combustion (IC) engines, the percentage gain in second law efficiency is even more pronounced. A process flow analysis allowing for likely irreversibilities shows that combining a CLC plant and a fleet of fuel cells, the overall efficiency of the system equals 40.8%, exceeding the performance of competing fuel powered technologies. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved. Source

Coppins M.,Imperial College London
Physical Review Letters | Year: 2010

A misty plasma is defined as a plasma containing small liquid droplets. In such a system, the droplets will undergo total electrostatic breakup if their charge exceeds the well-known Rayleigh limit. This imposes a minimum size on the droplets. Electrostatic breakup is a significant mechanism limiting droplet survival in a wide range of plasma applications, including plasma-enhanced chemical vapor deposition and fusion tokamaks. © 2010 The American Physical Society. Source

Hoare B.,Humboldt University of Berlin | Tseytlin A.A.,Imperial College London
Nuclear Physics B | Year: 2013

We consider superstring theory on AdS3×S3×T4 supported by a combination of RR and NSNS 3-form fluxes (with parameter of the NSNS 3-form q). This theory interpolates between the pure RR flux model (. q=0) whose spectrum is expected to be described by a (thermodynamic) Bethe ansatz and the pure NSNS flux model (. q=1) which is described by the supersymmetric extension of the SL(2,R)×SU(2) WZW model. As a first step towards the solution of this integrable theory for generic value of q we compute the corresponding tree-level S-matrix for massive BMN-type excitations. We find that this S-matrix has a surprisingly simple dependence on q: the diagonal amplitudes have exactly the same structure as in the q=0 case but with the BMN dispersion relation e2=p2+1 replaced by the one with shifted momentum and mass, e2=(p±q)2+1?q2. The off-diagonal amplitudes are then determined from the classical Yang-Baxter equation. We also construct the Pohlmeyer-reduced model corresponding to this superstring theory and find that it depends on q only through the rescaled mass parameter, μ→√1-q2μ, implying that its relativistic S-matrix is q-independent. © 2013 Elsevier B.V. Source

Tyrer P.,Imperial College London
Psychiatrist | Year: 2013

The aim for seamless care that has long been the ultimate goal of good community psychiatry in the UK has disappeared, and there is now much needless argument over models of delivering care that ignore its main philosophy. It is argued that this ossification of care has not only made it ineffective, but has also promoted demoralisation and burn-out in the workforce, as the locus of control has shifted from clinician to managerial imperative. An initiative that can break up the opaque structures that hinder continuity of care is now available and a suggestion is made for a flexible, invigorated community care team system based on smaller catchment areas that allows a single team to combine the elements of assertive outreach, crisis resolution and early intervention with in-patient care. Source

Rzepa H.S.,Imperial College London
Nature Chemistry | Year: 2010

The chemistry of helium has hitherto been confined to experimental and theoretical analysis of small molecules containing three to five atoms in the gas phase. Here a new suggestion is made for compounds of helium deriving from a recent proposal that five-coordinate carbon might be captured as a frozen SN2 transition state. A series of logical steps, originally discussed as postings and comments to two blogs, led to the outcome described here of a central hypervalent atom bound on one face by a small cyclic carbon ligand, with the other free face having an interaction to a helium atom with the topological properties of a charge-shift rather than a covalent bond. Although high-level theory predicts these helium bonds to be quite short with relatively high stretching frequencies, the kinetic barriers to the loss of helium are predicted to be small, and are not increased by the strategy of having bulky substituents on the ring ligand. © 2010 Macmillan Publishers Limited. All rights reserved. Source

Lucy L.B.,Imperial College London
Astronomy and Astrophysics | Year: 2012

Mass fluxes J are computed for the extragalactic O stars investigated by Tramper et al. (2011, ApJ, 741, 8-TSKK). For one early-type O star, computed and observed rates agree within errors. However, for two late-type O stars, theoretical mass-loss rates underpredict observed rates by ∼1.6 dex, far exceeding observational errors. A likely cause of the discrepancy is overestimated observed rates due to the neglect of wind-clumping. A less likely but intriguing possibility is that, in observing O stars with Z/Z · ∼ 1/7, TSKK have serendipitously discovered an additional mass-loss mechanism not evident in the spectra of Galactic O stars because of their powerful radiation-driven winds. Constraints on this unknown mechanism are discussed. In establishing that the discrepancies, if real, are inescapable for purely radiation-driven winds, failed searches for high-J solutions are reported and the importance stressed of a numerical technique that cannot spuriously create or destroy momentum. The Z-dependences of the computed rates for Z/Z · ∈ (1/30,2) show significant departures from a single power law, and these are attributed to curve-of-growth effects in the differentially expanding reversing layers. The best-fitting power-law exponents range from 0.68-0.97. © 2012 ESO. Source

Lucy L.B.,Imperial College London
Astronomy and Astrophysics | Year: 2012

A two-component phenomenological model developed originally for ζ Puppis is revised in order to model the outflows of late-type O dwarfs that exhibit the weak-wind phenomenon. With the theory's standard parameters for a generic weak-wind star, the ambient gas is heated to coronal temperatures ≈ 3 × 10 6 K at radii ≥ 1.4 R, with cool radiation-driven gas being then confined to dense clumps with filling factor ≈ 0.02. Radiative driving ceases at radius ≈ 2.1 R when the clumps are finally destroyed by heat conduction from the coronal gas. Thereafter, the outflow is a pure coronal wind, which cools and decelerates reaching ∞ with terminal velocity ≈ 1000 km-s -1. © 2012 ESO. Source

Wolz R.,Imperial College London
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention | Year: 2012

A robust automated segmentation of abdominal organs can be crucial for computer aided diagnosis and laparoscopic surgery assistance. Many existing methods are specialised to the segmentation of individual organs or struggle to deal with the variability of the shape and position of abdominal organs. We present a general, fully-automated method for multi-organ segmentation of abdominal CT scans. The method is based on a hierarchical atlas registration and weighting scheme that generates target specific priors from an atlas database by combining aspects from multi-atlas registration and patch-based segmentation, two widely used methods in brain segmentation. This approach allows to deal with high inter-subject variation while being flexible enough to be applied to different organs. Our results on a dataset of 100 CT scans compare favourable to the state-of-the-art with Dice overlap values of 94%, 91%, 66% and 94% for liver, spleen, pancreas and kidney respectively. Source

Vineis P.,Imperial College London | Wild C.P.,International Agency for Research on Cancer
The Lancet | Year: 2014

Cancer is a global and growing, but not uniform, problem. An increasing proportion of the burden is falling on low-income and middle-income countries because of not only demographic change but also a transition in risk factors, whereby the consequences of the globalisation of economies and behaviours are adding to an existing burden of cancers of infectious origin. We argue that primary prevention is a particularly effective way to fight cancer, with between a third and a half of cancers being preventable on the basis of present knowledge of risk factors. Primary prevention has several advantages: the effectiveness could have benefits for people other than those directly targeted, avoidance of exposure to carcinogenic agents is likely to prevent other non-communicable diseases, and the cause could be removed or reduced in the long term-eg, through regulatory measures against occupational or environmental exposures (ie, the preventive effort does not need to be renewed with every generation, which is especially important when resources are in short supply). Primary prevention must therefore be prioritised as an integral part of global cancer control. Source

Tan H.-L.,Imperial College London | Rosenthal M.,Royal Brompton Hospital
Thorax | Year: 2013

Interleukin 17 (IL-17) is a key proinflammatory cytokine in the T helper 17 pathway. While it is important in the clearance of certain pathogens, IL-17 has been shown to contribute to the pathogenesis of such inflammatory diseases as rheumatoid arthritis and psoriasis. In the lung, it has been postulated to be involved in the neutrophilic inflammation and airway remodelling of chronic respiratory conditions but the situation is increasingly complex. This review summarises the evidence for its role in several chronic inflammatory lung diseases: asthma, obliterative bronchiolitis, chronic obstructive pulmonary disease, sarcoidosis and cystic fibrosis. Source

Pournaras D.J.,Imperial College London
Current atherosclerosis reports | Year: 2013

The burden of type 2 diabetes is increasing. The prevention of the disease, improvement of metabolic control, and more importantly reduction in mortality remain a challenge for primary care doctors, diabetologists, researchers and policymakers. In this article, the available literature is reviewed with a focus on recent developments. Comparison between medical and surgical interventions is performed using mainly head-to-head trials where possible. Weight loss surgery is effective for glycaemic control. The need for level 1 data with hard end points such as cardiovascular risk and mortality is highlighted, and the prospect of the combination of existing therapy options is emphasized. Source

Shovlin C.L.,Imperial College London
Blood Reviews | Year: 2010

Hereditary haemorrhagic telangiectasia, inherited as an autosomal dominant trait, affects approximately 1 in 5000 people. The abnormal vascular structures in HHT result from mutations in genes (most commonly endoglin or ACVRL1) whose protein products influence TGF-ß superfamily signalling in vascular endothelial cells. The cellular mechanisms underlying the generation of HHT telangiectasia and arteriovenous malformations are being unravelled, with recent data focussing on a defective response to angiogenic stimuli in particular settings. For affected individuals, there is often substantial morbidity due to sustained and repeated haemorrhages from telangiectasia in the nose and gut. Particular haematological clinical challenges include the management of severe iron deficiency anaemia; handling the intricate balance of antiplatelet or anticoagulants for HHT patients in whom there are often compelling clinical reasons to use such agents; and evaluation of apparently attractive experimental therapies promoted in high profile publications when guidelines and reviews are quickly superseded. There is also a need for sound screening programmes for silent arteriovenous malformations. These occur commonly in the pulmonary, cerebral, and hepatic circulations, may haemorrhage, but predominantly result in more complex pathophysiology due to consequences of defective endothelium, or shunts that bypass specific capillary beds. This review will focus on the new evidence and concepts in this complex and fascinating condition, placing these in context for both clinicians and scientists, with a particular emphasis on haematological settings. © 2010 Elsevier Ltd. Source

Wobbe L.,Bielefeld University | Nixon P.J.,Imperial College London
Nucleic Acids Research | Year: 2013

The molecular function of mTERFs (mitochondrial transcription termination factors) has so far only been described for metazoan members of the protein family and in animals they control mitochondrial replication, transcription and translation. Cells of photosynthetic eukaryotes harbour chloroplasts and mitochondria, which are in an intense cross-talk that is vital for photosynthesis. Chlamydomonas reinhardtii is a unicellular green alga widely used as a model organism for photosynthesis research and green biotechnology. Among the six nuclear C. reinhardtii mTERF genes is mTERF-like gene of Chlamydomonas (MOC1), whose inactivation alters mitorespiration and interestingly also light-acclimation processes in the chloroplast that favour the enhanced production of biohydrogen. We show here from in vitro studies that MOC1 binds specifically to a sequence within the mitochondrial rRNA-coding module S3, and that a knockout of MOC1 in the mutant stm6 increases read-through transcription at this site, indicating that MOC1 acts as a transcription terminator in vivo. Whereas the level of certain antisense RNA species is higher in stm6, the amount of unprocessed mitochondrial sense transcripts is strongly reduced, demonstrating that a loss of MOC1 causes perturbed mitochondrial DNA (mtDNA) expression. Overall, we provide evidence for the existence of mitochondrial antisense RNAs in C. reinhardtii and show that mTERF-mediated transcription termination is an evolutionary-conserved mechanism occurring in phototrophic protists and metazoans. © 2013 The Author(s) 2013. Published by Oxford University Press. Source

Franks S.,Imperial College London
Journal of Family Planning and Reproductive Health Care | Year: 2012

Excess male-pattern body hair in women is a very common and psychologically damaging condition. Although its cause is usually a chronic and benign disorder (most commonly polycystic ovary syndrome) it may rarely be an indication of a more serious endocrine disease such as Cushing syndrome or an androgen-secreting tumour. Investigations do not usually need to be extensive, but effective management is important, irrespective of cause, for what can be a debilitating symptom. Specific treatment of any underlying disease is important but in most cases treatment is empirical; it may simply involve physical hair removal, ideally by electrolysis or laser treatment. However, endocrine therapy to suppress androgen production and/or action is desirable in many, if not most, cases. Source

Evans T.S.,Imperial College London
Journal of Statistical Mechanics: Theory and Experiment | Year: 2010

It is shown how to construct a clique graph in which properties of cliques of a fixed order in a given graph are represented by vertices in a weighted graph. Various definitions and motivations for these weights are given. The detection of communities or clusters is used to illustrate how a clique graph may be exploited. In particular a benchmark network is shown where clique graphs find the overlapping communities accurately while vertex partition methods fail. ©2010 IOP Publishing Ltd and SISSA. Source

Summary: Recent major cancer genome sequencing studies have used whole-genome sequencing to detect various types of genomic variation. However, a number of these studies have continued to rely on SNP array information to provide additional results for copy number and loss-of-heterozygosity estimation and assessing tumour purity. OncoSNP-SEQ is a statistical model-based approach for inferring copy number profiles directly from high-coverage whole genome sequencing data that is able to account for unknown tumour purity and ploidy. © The Author 2013. Source

Ashton-Rickardt P.G.,Imperial College London
Cell Metabolism | Year: 2016

The development and function of cytotoxic CD8 T cells (CTLs), which provide immunity to viral infections, are regulated by changes in mitochondrial respiration. Champagne et al. (2016) describe a new mechanism through which mitochondrial metabolism controls production of ATP required for the secretion of critical anti-viral molecules by CTLs. © 2016 Elsevier Inc. Source

Williams M.,Imperial College London
Journal of Instrumentation | Year: 2010

Multivariate analyses play an important role in high energy physics. Such analyses often involve performing an unbinned maximum likelihood fit of a probability density function (p.d.f.) to the data. This paper explores a variety of unbinned methods for determining the goodness of fit of the p.d.f. to the data. The application and performance of each method is discussed in the context of a real-life high energy physics analysis (a Dalitz-plot analysis). Several of the methods presented in this paper can also be used for the non-parametric determination of whether two samples originate from the same parent p.d.f. This can be used, e.g., to determine the quality of a detector Monte Carlo simulation without the need for a parametric expression of the efficiency. © 2010IOP Publishing Ltd and SISSA. Source

Murakami R.,Konan University | Bismarck A.,Imperial College London
Advanced Functional Materials | Year: 2010

Oil (liquids with low surface tension and practically immiscible with water) drops can be dispersed in air if relatively oleophobic particles are available. However, such particles with oil-repellent surfaces cannot simply be prepared by controlling the particle surface chemistry alone. Herein the preparation of oil-in-air materials (oil marbles, dry oils) by changing the wetting behavior of particles by tuning the oil properties, which allows the formation of the metastable Cassie-Baxter wetting state of particle assemblies on oil drop surfaces, is presented. The oil-in-air materials can be converted to air-in-oil materials (non-aqueous foams) by tailoring the oil properties, as the robustness of the metastable Cassie-Baxter state of the particle assemblies critically depends on the particle wettability. This conversion implies the phase inversion of dispersed systems consisting of air and oils. It is also shown that particle-stabilized non-aqueous foams can be utilized as template to produce macroporous polymers. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA,. Source

Walters J.R.F.,Imperial College London
Expert Review of Gastroenterology and Hepatology | Year: 2010

Chronic diarrhea due to bile acid malabsorption may be considered as contributing to the diagnosis when it results from secondary causes, such as ileal resection affecting the enterohepatic circulation. However, the primary form (also known as idiopathic bile acid malabsorption) is not well recognized as a common condition and patients are left undiagnosed. Primary bile acid diarrhea can be diagnosed by the nuclear medicine 75Se- homocholyltaurine (SeHCAT) test, although this is unavailable or underutilized in many settings. A systematic review suggests that approximately 30% of patients who would otherwise be diagnosed with diarrhea-predominant irritable bowel syndrome or functional diarrhea have abnormal SeHCAT retention. Serum 7α-hydroxy-4-cholesten-3-one can also be measured to show increased bile acid synthesis. The reasons for the lack of recognition of primary bile acid diarrhea are discussed, and these are compared with the other common cause of malabsorption, celiac disease. The lack of a clear pathophysiological mechanism has been a problem, but recent evidence suggests that impaired feedback control of hepatic bile acid synthesis by the ileal hormone FGF19 results in overproduction of bile acids. The identification of FGF19 as the central mechanism opens up new areas for development in the diagnosis and treatment of primary bile acid diarrhea. © 2010 Expert Reviews Ltd. Source

Huckvale C.,Imperial College London
Quality & safety in health care | Year: 2010

BACKGROUND: Research on patient care has identified substantial variations in the quality and safety of healthcare and the considerable risks of iatrogenic harm as significant issues. These failings contribute to the high rates of potentially avoidable morbidity and mortality and to the rising levels of healthcare expenditure seen in many health systems. There have been substantial developments in information technology in recent decades and there is now real potential to apply these technological developments to improve the provision of healthcare universally. Of particular international interest is the use of eHealth applications. There is, however, a large gap between the theoretical and empirically demonstrated benefits of eHealth applications. While these applications typically have the technical capability to help professionals in the delivery of healthcare, inadequate attention to the socio-technical dimensions of their use can result in new avoidable risks to patients. RESULTS AND DISCUSSION: Given the current lack of evidence on quality and safety improvements and on the cost-benefits associated with the introduction of eHealth applications, there should be a focus on implementing more mature technologies; it is also important that eHealth applications should be evaluated against a comprehensive and rigorous set of measures, ideally at all stages of their application life cycle. Source

Aggarwal R.,Imperial College London
Quality & safety in health care | Year: 2010

Simulation-based medical education enables knowledge, skills and attitudes to be acquired for all healthcare professionals in a safe, educationally orientated and efficient manner. Procedure-based skills, communication, leadership and team working can be learnt, be measured and have the potential to be used as a mode of certification to become an independent practitioner. Simulation-based training initially began with life-like manikins and now encompasses an entire range of systems, from synthetic models through to high fidelity simulation suites. These models can also be used for training in new technologies, for the application of existing technologies to new environments and in prototype testing. The level of simulation must be appropriate to the learners' needs and can range from focused tuition to mass trauma scenarios. The development of simulation centres is a global phenomenon which should be encouraged, although the facilities should be used within appropriate curricula that are methodologically sound and cost-effective. A review of current techniques reveals that simulation can successfully promote the competencies of medical expert, communicator and collaborator. Further work is required to develop the exact role of simulation as a training mechanism for scholarly skills, professionalism, management and health advocacy. Source

Newton R.C.,Imperial College London
Quality & safety in health care | Year: 2010

Technology, equipment and medical devices are vital for effective healthcare throughout the world but are associated with risks. These risks include device failure, inappropriate use, insufficient user-training and inadequate inspection and maintenance. Further risks within the developing world include challenging conditions of temperature and humidity, poor infrastructure, poorly trained service providers, limited resources and supervision, and inappropriately complex equipment being supplied without backup training for its use or maintenance. This document is the product of an expert working group established by WHO Patient Safety to define the measures being taken to reduce these risks. It considers how the provision of safer technology services worldwide is being enhanced in three ways: through non-punitive and open reporting systems of technology-related adverse events and near-misses, with classification and investigation; through healthcare quality assessment, accreditation and certification; and by the investigation of how appropriate design and an understanding of the conditions of use and associated human factors can improve patient safety. Many aspects of these steps remain aspirational for developing countries, where highly disparate needs and a vast range of technology-related problems exist. Here, much greater emphasis must be placed on failsafe, durable and user-friendly design--examples of which are described. Source

Spratt B.G.,Imperial College London
Journal of Antimicrobial Chemotherapy | Year: 2012

In this review, based on my Garrod Lecture to the British Society for Antimicrobial Chemotherapy, I have given a brief outline of my career over the past 40 years, starting with research in the 1970s into the properties and functions of penicillin-binding proteins (PBPs), leading to the identification of the high molecular mass PBPs as the physiological targets of penicillin, and subsequent studies showing the emergence of low-affinity PBPs in penicillin-resistant clinical isolates by inter-species recombination and the generation of mosaic PBP genes. The studies of clinical isolates of gonococci, meningococci and pneumococci with PBP-mediated resistance to penicillin led to new interests in molecular epidemiology and the population and evolutionary biology of bacterial pathogens. The development (with colleagues) of multilocus sequence typing provided a method for the unambiguous characterization of bacterial strains that has proved to be very widely used, but the recent remarkable (and ongoing) developments in DNA sequencing technologies have provided the prospect of being able routinely to use whole genome sequences to characterize pathogen isolates. These developments will soon have major implications for diagnostic microbiology, outbreak investigations and our ability to follow the spread of strains of community-acquired and nosocomial pathogens at local, national and international levels. However, there are major barriers to be overcome, particularly with respect to how the avalanche of genome sequence data will be stored so that its transformative potential for molecular epidemiology and international public health are fully realized. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. Source

Majeed A.,Imperial College London
Journal of Ambulatory Care Management | Year: 2012

Many European countries have well-developed health systems that offer universal access to health services and which have a strong primary care sector. However, as the financial crisis in Europe progresses, it is leading to significant cutbacks in publicly funded health services. A key objective for primary care physicians will therefore be to work in an environment where resources will be much more limited than in the past. In the longer term, the role of primary care physicians in European health systems will continue to expand to meet the aim of shifting health services to the generally more cost-effective setting of primary care. Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

Burt A.,Imperial College London
Philosophical transactions of the Royal Society of London. Series B, Biological sciences | Year: 2014

Mosquito-borne diseases are causing a substantial burden of mortality, morbidity and economic loss in many parts of the world, despite current control efforts, and new complementary approaches to controlling these diseases are needed. One promising class of new interventions under development involves the heritable modification of the mosquito by insertion of novel genes into the nucleus or of Wolbachia endosymbionts into the cytoplasm. Once released into a target population, these modifications can act to reduce one or more components of the mosquito population's vectorial capacity (e.g. the number of female mosquitoes, their longevity or their ability to support development and transmission of the pathogen). Some of the modifications under development are designed to be self-limiting, in that they will tend to disappear over time in the absence of recurrent releases (and hence are similar to the sterile insect technique, SIT), whereas other modifications are designed to be self-sustaining, spreading through populations even after releases stop (and hence are similar to traditional biological control). Several successful field trials have now been performed with Aedes mosquitoes, and such trials are helping to define the appropriate developmental pathway for this new class of intervention. Source

Intuitive and easily-described, "pick-the-highest" is often recommended for quantitative optimization of AV and especially VV delay settings of biventricular pacemakers (BVP; cardiac resynchronization therapy, CRT). But reliable selection of the optimum setting is challenged by beat-to-beat physiological variation, which "pick-the-highest" combats by averaging multiple heartbeats. Optimization is not optimization unless the optimum is identified confidently. This document shows how to calculate how many heartbeats must be averaged to optimize reliably by pick-the-highest. Any reader, by conducting a few measurements, can calculate for locally-available methods (i) biological scatter between replicate measurements, and (ii) curvature of the biological response. With these, for any clinically-desired precision of optimization, the necessary number of heartbeats can be calculated. To achieve 95% confidence of getting within ±Δx of the true optimum, the number of heartbeats needed is 2(scatter/curvature)2/Δx 4 per setting. Applying published scatter/curvature values (which readers should re-evaluate locally) indicates that optimizing AV, even coarsely with a 40 ms-wide band of precision, requires many thousand beats. For VV delay, the number approaches a million. Moreover, identifying the optimum twice as precisely requires 30-fold more beats. "Pick the highest" is quick to say but slow to do. We must not expect staff to do the impossible; nor criticise them for not doing so. Nor should we assume recommendations and published protocols are well-designed. Reliable AV or VV optimization, using "pick-the-highest" on commonly-recommended manual measurements, is unrealistic. Improving time-efficiency of the optimization process to become clinically realistic may need a curve-fitting strategy instead, with all acquired data marshalled conjointly. © 2012 Elsevier Ireland Ltd. Source

Gentleman S.M.,Imperial College London
Neuropathology and Applied Neurobiology | Year: 2013

Microglia cells have been implicated, to some extent, in the pathogenesis of all of the common neurodegenerative disorders involving protein aggregation such as Alzheimer's disease, Parkinson's disease and Amyotrophic Lateral Sclerosis. However, the precise role they play in the development of the pathologies remains unclear and it seems that they contribute to the pathological process in different ways depending on the specific disorder. A better understanding of their varied roles is essential if they are to be the target for novel therapeutic strategies. © 2013 British Neuropathological Society. Source

Pautasso M.,Imperial College London
Scientometrics | Year: 2010

The file-drawer problem is the tendency of journals to preferentially publish studies with statistically significant results. The problem is an old one and has been documented in various fields, but to my best knowledge there has not been attention to how the issue is developing in a quantitative way through time. In the abstracts of various major scholarly databases (Science and Social Science Citation Index (1991-2008), CAB Abstracts and Medline (1970s-2008), the file drawer problem is gradually getting worse, in spite of an increase in (1) the total number of publications and (2) the proportion of publications reporting both the presence and the absence of significant differences. The trend is confirmed for particular natural science topics such as biology, energy and environment but not for papers retrieved with the keywords biodiversity, chemistry, computer, engineering, genetics, psychology and quantum (physics). A worsening file-drawer problem can be detected in various medical fields (infection, immunology, malaria, obesity, oncology and pharmacology), but not for papers indexed with strings such as AIDS/HIV, epidemiology, health and neurology. An increase in the selective publication of some results against some others is worrying because it can lead to enhanced bias in meta-analysis and hence to a distorted picture of the evidence for or against a certain hypothesis. Long-term monitoring of the file-drawer problem is needed to ensure a sustainable and reliable production of (peer-reviewed) scientific knowledge. © 2010 Akadémiai Kiadó, Budapest, Hungary. Source

Timotheou S.,Imperial College London
Computer Journal | Year: 2010

The random neural network (RNN) is a recurrent neural network model inspired by the spiking behaviour of biological neuronal networks. Contrary to most artificial neural network models, neurons in the RNN interact by probabilistically exchanging excitatory and inhibitory spiking signals. The model is described by analytical equations, has a low complexity supervised learning algorithm and is a universal approximator for bounded continuous functions. The RNN has been applied in a variety of areas including pattern recognition, classification, image processing, combinatorial optimization and communication systems. It has also inspired research activity in modelling interacting entities in various systems such as queueing and gene regulatory networks. This paper presents a review of the theory, extension models, learning algorithms and applications of the RNN. Source

Vancheri C.,University of Catania | Du Bois R.M.,Imperial College London
European Respiratory Journal | Year: 2013

Idiopathic pulmonary fibrosis (IPF) is a progressive fibroproliferative disease that results in increasing morbidity. To date there is only one licensed therapy for this condition and other agents are needed for this attritional disease. Efforts to study other agents have been obstructed by an increasing division of opinion about the most clinically meaningful end-point of phase III clinical trials to demonstrate efficacy. Many clinicians believe that an agent that impedes progression of the disease is more than acceptable and will encourage the pharmaceutical industry to further develop their IPF programmes. We have been impressed by the behavioural and biological similarities of cancer and IPF, and wondered if lessons could be learned about clinical trial design from lung cancer studies. Here, we set out our arguments that the similarities with cancer justify comparing the magnitude of therapeutic effects in clinical trials in nonsmall cell lung cancer with those in successful trials in IPF. We demonstrate that efficacy is of a similar magnitude in the two chronic lung diseases. We recommend that the demonstration of similar magnitudes of progression-free disease effect in IPF, using appropriate indices, should be considered as clinically meaningful benefit in future phase III clinical trials of novel therapies. Source

Spagnolo P.,University of Modena and Reggio Emilia | Fabbri L.M.,University of Modena and Reggio Emilia | Bush A.,Imperial College London
European Respiratory Journal | Year: 2013

Long-term macrolide treatment was first shown to alter the natural history of diffuse panbronchiolitis (DPB) in the late 1980s. Since then, macrolides have been demonstrated to exert antiinflammatory and immunomodulatory activity in addition to being antimicrobial. Indeed, their spectrum of action extends to the regulation of leukocyte function and production of inflammatory mediators, control of mucus hypersecretion, resolution of inflammation and modulation of host defence mechanisms. As such, the potential benefit of macrolide antibiotics has been evaluated in a variety of chronic respiratory diseases. The best studied condition is cystic fibrosis, of which there have been six randomised controlled trials showing evidence of benefit. However, most of the studies were limited by small numbers of patients and short follow-up. More recently, landmark studies have demonstrated the efficacy of azithromycin in reducing the risk of acute exacerbations in patients with chronic obstructive pulmonary disease, but the optimal duration and dosing of macrolide treatment remain uncertain. With the exception of patients with DPB and cystic fibrosis, until clear evidence of efficacy is available, the long-term use of macrolides should be limited to highly selected patients after careful evaluation of benefit and harm, or in the context of randomised controlled clinical trials. Copyright © ERS 2013. Source

Gorog D.A.,Imperial College London | Fuster V.,Mount Sinai School of Medicine
Journal of the American College of Cardiology | Year: 2013

This review is a critical evaluation of publications in the past decade on the usefulness of platelet function tests (PFTs) in clinical cardiology, in aiding diagnosis, predicting risk, and monitoring therapy. The ideal PFT should: 1) detect baseline platelet hyperreactivity; 2) allow individualization of antiplatelet medication; 3) predict thrombotic risk; and 4) predict bleeding risk. The practicalities of clinical cardiology demand rapid, accurate, and reliable tests that are simple to operate at the bedside and available 24 h a day, 7 days a week. Point-of-care PFTs most widely evaluated clinically include PFA-100 and VerifyNow. None of these tests can reliably detect platelet hyperreactivity and thus identify a prothrombotic state. Identification of antiplatelet nonresponsiveness or hyporesponsiveness is highly test specific, and does not allow individualization of therapy. The power of PFTs in predicting thrombotic events for a given individual is variable and often modest, and alteration of antithrombotic treatment on the basis of the results of PFTs has not been shown to alter clinical outcome. PFTs in current mainstream use cannot reliably assess bleeding risk. These tests have been in use for over a decade, but the hopes raised by PFTs in clinical practice remain unfulfilled. Although physiologically relevant measurement of platelet function now is more important than ever, a critical reappraisal of available techniques in light of clinical requirements is needed. The use of native blood, global stimulus instead of individual agonists, contribution of thrombin generation by activated platelets to the test results, and establishment of a PFT therapeutic range for each antiplatelet drug should be considered and is discussed. © 2013 American College of Cardiology Foundation. Source

Harrison J.,Imperial College London
Medical Clinics of North America | Year: 2013

In this article, cognitive measures in the screening of individuals at risk for Alzheimer disease (AD) are reviewed. Use of cognitive tasks in identifying clinical cases of AD is considered, as well as methods for detecting those in the prodromal stages of the disease, including cognitive screening instruments. Traditional assessments, such as the mini-mental state examination, as well as contemporary computerized screening instruments, are examined. Areas of cognition for investigation in the detection of prodromal AD are recommended. The prospects for general cognitive screening are reviewed, and more engaging technologies to tests individuals at risk for developing AD are recommended. © 2013 Elsevier Inc. Source

Howard L.S.,Imperial College London | Hughes R.J.,Northern General Hospital
Thorax | Year: 2013

The National Institute for Health and Clinical Excellence recently published a clinical guideline on the management of venous thromboembolic disease and thrombophilia testing. Several stand-out recommendations are made which may be practice changing for many physicians, such as catheter-directed thrombolysis for ilio-femoral deep venous thrombosis, routine cancer screening and extended duration of anticoagulation for unprovoked events. In this article, we summarise the key points of the guideline and discuss remaining areas of controversy. Source

Diaz M.B.,Imperial College London
Chaos (Woodbury, N.Y.) | Year: 2010

We present a dynamical model for rewiring and attachment in bipartite networks. Edges are placed between nodes that belong to catalogs that can either be fixed in size or growing in size. The model is motivated by an empirical study of data from the video rental service Netflix, which invites its users to give ratings to the videos available in its catalog. We find that the distribution of the number of ratings given by users and that of the number of ratings received by videos both follow a power law with an exponential cutoff. We also examine the activity patterns of Netflix users and find bursts of intense video-rating activity followed by long periods of inactivity. We derive ordinary differential equations to model the acquisition of edges by the nodes over time and obtain the corresponding time-dependent degree distributions. We then compare our results with the Netflix data and find good agreement. We conclude with a discussion of how catalog models can be used to study systems in which agents are forced to choose, rate, or prioritize their interactions from a large set of options. © 2010 American Institute of Physics. Source

Furlong M.J.,University of Queensland | Wright D.J.,Imperial College London | Dosdall L.M.,University of Alberta
Annual Review of Entomology | Year: 2013

Agricultural intensification and greater production of Brassica vegetable and oilseed crops over the past two decades have increased the pest status of the diamondback moth (DBM), Plutella xylostella L., and it is now estimated to cost the world economy US$4-5 billion annually. Our understanding of some fundamental aspects of DBM biology and ecology, particularly host plant relationships, tritrophic interactions, and migration, has improved considerably but knowledge of other aspects, e.g., its global distribution and relative abundance, remains surprisingly limited. Biological control still focuses almost exclusively on a few species of hymenopteran parasitoids. Although these can be remarkably effective, insecticides continue to form the basis of management; their inappropriate use disrupts parasitoids and has resulted in field resistance to all available products. Improved ecological understanding and the availability of a series of highly effective selective insecticides throughout the 1990s provided the basis for sustainable and economically viable integrated pest management (IPM) approaches. However, repeated reversion to scheduled insecticide applications has resulted in resistance to these and more recently introduced compounds and the breakdown of IPM programs. Proven technologies for the sustainable management of DBM currently exist, but overcoming the barriers to their sustained adoption remains an enormous challenge. © 2013 by Annual Reviews. All rights reserved. Source

Sootla A.,Imperial College London
IEEE Transactions on Automatic Control | Year: 2013

This technical note is dedicated to model order reduction of linear time-invariant systems. The main contribution of this technical note is the derivation of two scalable stability-preserving model reduction algorithms. Both algorithms constitute a development of a recently proposed model reduction method. The algorithms perform a curve fitting procedure using frequency response samples of a model and semidefinite programming methods. Computation of these samples can be done efficiently even for large scale models. Both algorithms are obtained from a reformulation of the model reduction problem. One proposes a semidefinite relaxation, while the other is an iterative semidefinite approach. The relaxation approach is similar to Hankel model reduction, which is a well-known and established method in the control literature. Due to this resemblance, the accuracy of approximation is also similar to the one of Hankel model reduction. An appealing quality of the proposed algorithms is the ability to easily perform extensions, e.g., introduce frequency-weighting, positive-real and bounded-real constraints. © 1963-2012 IEEE. Source

Mulligan C.E.A.,Imperial College London | Olsson M.,Ericsson AB
IEEE Communications Magazine | Year: 2013

Smart cities have rapidly become a hot topic within technology communities, and promise both improved delivery of services to end users and reduced environmental impact in an era of unprecedented urbanization. Both large hightech companies and grassroots citizen-led initiatives have begun exploring the potential of these technologies. Significant barriers remain to the successful rollout and deployment of business models outlined for smart city applications and services, however. Most of these barriers pertain to an ongoing battle between two main schools of thought for system architecture, ICT and telecommunications, proposed for data management and service creation. Both of these system architectures represent a certain type of value chain and the legacy perspective of the respective players that wish to enter the smart city arena. Smart cities services, however, utilize components of both the ICT industry and mobile telecommunications industries, and do not benefit from the current binary perspective of system architecture. The business models suggested for the development of smart cities require a longterm strategic view of system architecture evolution. This article discusses the architectural evolution required to ensure that the rollout and deployment of smart city technologies is smooth through acknowledging and integrating the strengths of both the system architectures proposed. © 2013 IEEE. Source

Fenwick A.,Imperial College London
Public Health | Year: 2012

The first comprehensive study on the global burden of disease and risk factors was commissioned by the World Bank in 1992. A follow-up study was performed in 2005, and another iteration was commissioned by the World Health Organization in 2010, due for publication in 2011. The author suggests that the global burden of neglected tropical diseases (NTDs) has been seriously underestimated. The way forward is the integration of control efforts, with programmes coming together to deliver a package of drugs against NTDs. Barriers to continent-wide coverage of drugs against NTDs are political will (missing in those countries with poor governance), funding (approximately half of the $1.5-2 billion is needed) and human resources. However, if the donors who give so much to malaria, tuberculosis and human immunodeficiency virus would share just 10% of the amount allocated to the big three, the most common NTDs could become diseases of the past. This could well happen within 7 years, and the targets of GET2020 (Global Elimination of Trachoma by 2020) to eliminate trachoma and GAELF (the Global Alliance to Eliminate Lymphatic Filariasis) to eliminate lymphatic filariasis by 2020 are achievable. © 2011 The Royal Society for Public Health. Source

Girolami D.,University of Nottingham | Tufarelli T.,Imperial College London | Adesso G.,University of Nottingham
Physical Review Letters | Year: 2013

Quantum mechanics predicts that measurements of incompatible observables carry a minimum uncertainty which is independent of technical deficiencies of the measurement apparatus or incomplete knowledge of the state of the system. Nothing yet seems to prevent a single physical quantity, such as one spin component, from being measured with arbitrary precision. Here, we show that an intrinsic quantum uncertainty on a single observable is ineludible in a number of physical situations. When revealed on local observables of a bipartite system, such uncertainty defines an entire class of bona fide measures of nonclassical correlations. For the case of 2×d systems, we find that a unique measure is defined, which we evaluate in closed form. We then discuss the role that these correlations, which are of the "discord" type, can play in the context of quantum metrology. We show in particular that the amount of discord present in a bipartite mixed probe state guarantees a minimum precision, as quantified by the quantum Fisher information, in the optimal phase estimation protocol. © 2013 American Physical Society. Source

Lovett M.,Imperial College London
Human Molecular Genetics | Year: 2013

We all start out as a single totipotent cell that is programmed to produce amulticellular organism. How do individual cells make those complex developmental switches? How do single cells within a tissue or organ differ, how do they coordinate their actions or go astray in a disease process? These are long-standing and fundamental questions in biology that are now becoming tractable because of advances in microfluidics, DNA amplificationandDNAsequencing. Methods for studying single-cell transcriptomes (or at least thepolyadenylatedmRNA fraction of it) are by far the furthest ahead and reveal remarkable heterogeneity between morphologically identical cells. The analysis of genomicDNAvariation is not far behind. The other 'omics' of single cells pose greater technological obstacles, but they are progressing and promise to yield highly integrated large data sets in the near future. © The Author 2013. Published by Oxford University Press. All rights reserved. Source

Leader E.,Imperial College London
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

There are now five angular momentum relations or sum rules in the literature: the Jaffe, Manohar relation for a longitudinally polarized nucleon, and the Bakker, Leader, Trueman result for the case of transverse polarization; the Ji relation for longitudinal polarization, and the Leader result for transverse polarization, both involving generalized parton distributions; and a new sum rule due to Ji, Xiong and Yuan dealing with the transverse component of the Pauli-Lubanski vector. I discuss these various relations and examine their precise interpretation in the light of the so-called "angular momentum controversy". In particular, I show that the claim of Ji, Xiong, Yuan that their Pauli-Lubanski relation is frame or energy independent is incorrect and that they have missed an energy dependent term in their expression. © 2013 Elsevier B.V. Source

Gath-Geva (GG) algorithm is one of the most popular methodologies for fuzzy c-means (FCM)-type clustering of data comprising numeric attributes; it is based on the assumption of data deriving from clusters of Gaussian form, a much more flexible construction compared to the spherical clusters assumption of the original FCM. In this paper, we introduce an extension of the GG algorithm to allow for the effective handling of data with mixed numeric and categorical attributes. Traditionally, fuzzy clustering of such data is conducted by means of the fuzzy k-prototypes algorithm, which merely consists in the execution of the original FCM algorithm using a different dissimilarity functional, suitable for attributes with mixed numeric and categorical attributes. On the contrary, in this work we provide a novel FCM-type algorithm employing a fully probabilistic dissimilarity functional for handling data with mixed-type attributes. Our approach utilizes a fuzzy objective function regularized by Kullback-Leibler (KL) divergence information, and is formulated on the basis of a set of probabilistic assumptions regarding the form of the derived clusters. We evaluate the efficacy of the proposed approach using benchmark data, and we compare it with competing fuzzy and non-fuzzy clustering algorithms. © 2011 Elsevier Ltd. All rights reserved. Source

Lee C.F.,Imperial College London
New Journal of Physics | Year: 2013

I study the confinement-induced aggregation phenomenon in a minimal model of self-propelled particles inside a channel. Starting from first principles, I derive a set of equations that govern the density profile of such a system at the steady-state, and calculate analytically how the aggregation at the walls varies with the physical parameters of the system. I also investigate how the gradient of the particle density varies if the inside of the channel is partitioned into two regions within which the active particles exhibit distinct levels of fluctuations in their directions of travel. © IOP Publishing and Deutsche Physikalische Gesellschaft. Source

Chandrawati R.,Imperial College London | Caruso F.,University of Melbourne
Langmuir | Year: 2012

Liposomes and polymersomes have attracted significant attention and have emerged as versatile materials for therapeutic delivery and in the design of artificial cells and organelles. Through the judicious choice of building blocks, these synthetic carriers can be readily engineered with tailored interfacial properties, offering new possibilities for the design of advanced assemblies with specific permeability, stability, stimuli response, and targeting capabilities. In this feature article, we highlight recent studies on biomimetic liposome- and polymersome-based multicompartmentalized assemblies en route toward the development of artificial cells, microreactors, and therapeutic delivery carriers. The strategies employed to produce these carriers are outlined, and the properties that contribute to their performance are discussed. Applications of these biomimetic assemblies are highlighted, and finally, areas that require additional investigation for the future development of these assemblies as next-generation therapeutic systems are outlined. © 2012 American Chemical Society. Source

Rose S.J.,Imperial College London
High Energy Density Physics | Year: 2013

Estimates are provided of the formation of electron-positron pairs from γ-γ annihilation in a plasma under conditions of thermonuclear burn in inertial confinement fusion (ICF). Based on values of density, temperature and plasma size that are representative of both burning DT and D plasmas in current and potential future ICF schemes, we estimate the radiation field present and from that calculate the electron-positron generation. In the most extreme conditions considered here, positron number densities of over 1023cm-3 are predicted. © 2013 Elsevier B.V. Source

Figueras P.,University of Cambridge | Wiseman T.,Imperial College London
Physical Review Letters | Year: 2013

We explore use of the harmonic Einstein equations to numerically find stationary black holes where the problem is posed on an ingoing slice that extends into the interior of the black hole. Requiring no boundary conditions at the horizon beyond smoothness of the metric, this method may be applied for horizons that are not Killing. As a nontrivial illustration we find black holes which, via AdS-CFT, describe a time-independent CFT plasma flowing through a static spacetime which asymptotes to Minkowski in the flow's past and future, with a varying spatial geometry in between. These are the first nonperturbative examples of stationary black holes which do not have Killing horizons. When the CFT spacetime slowly varies, the CFT stress tensor derived from gravity is well described by viscous hydrodynamics. For fast variation it is not, and the solutions are stationary analogs of dynamical quenches, with the plasma being suddenly driven out of equilibrium. We find evidence these flows become unstable for sufficiently strong quenches, and speculate the instability may be turbulent. © 2013 American Physical Society. Source

Henson J.,Imperial College London
Foundations of Physics | Year: 2013

This paper addresses arguments that "separability" is an assumption of Bell's theorem, and that abandoning this assumption in our interpretation of quantum mechanics (a position sometimes referred to as "holism") will allow us to restore a satisfying locality principle. Separability here means that all events associated to the union of some set of disjoint regions are combinations of events associated to each region taken separately. In this article, it is shown that: (a) localised events can be consistently defined without implying separability; (b) the definition of Bell's locality condition does not rely on separability in any way; (c) the proof of Bell's theorem does not use separability as an assumption. If, inspired by considerations of non-separability, the assumptions of Bell's theorem are weakened, what remains no longer embodies the locality principle. Teller's argument for "relational holism" and Howard's arguments concerning separability are criticised in the light of these results. Howard's claim that Einstein grounded his arguments on the incompleteness of QM with a separability assumption is also challenged. Instead, Einstein is better interpreted as referring merely to the existence of localised events. Finally, it is argued that Bell rejected the idea that separability is an assumption of his theorem. © 2013 Springer Science+Business Media New York. Source

Malijevsky A.,Institute of Chemical Technology Prague | Parry A.O.,Imperial College London
Physical Review Letters | Year: 2013

We present results of a microscopic density functional theory study of wedge filling transitions, at a right-angle wedge, in the presence of dispersionlike wall-fluid forces. Far from the corner the walls of the wedge show a first-order wetting transition at a temperature Tw which is progressively closer to the bulk critical temperature Tc as the strength of the wall forces is reduced. In addition, the meniscus formed near the corner undergoes a filling transition at a temperature Tf< Tw, the value of which is found to be in excellent agreement with macroscopic predictions. We show that the filling transition is first order if it occurs far from the critical point but is continuous if Tf is close to Tc even though the walls still show first-order wetting behavior. For this continuous transition the distance of the meniscus from the apex grows as ℓw≈(Tf-T) -βw with the critical exponent βw≈ 0.46±0.05 in good agreement with the phenomenological effective Hamiltonian prediction. Our results suggest that critical filling transitions, with accompanying large scale universal interfacial fluctuation effects, are more generic than thought previously, and are experimentally accessible. © 2013 American Physical Society. Source

Lattimer C.R.,Imperial College London
International Angiology | Year: 2014

Chronic venous disease (CVD) affects approximately a quarter of the adult population and causes a considerable burden on the health of these patients. The true extent of the severity of the disease is hampered because of reduced public awareness, operational difficulties in diagnosis, and the perception that varicose veins are mainly a cosmetic inconvenience. Consequently the disease receives little attention in public health care systems which focus on life threatening conditions and those which cause obvious morbidity like cancer, cardiac disease and stroke. This review aims to correct these misconceptions by addressing the full scope of CVD, including the post-thrombotic syndrome and venous ulceration. The severity of conditions like telangectasiae and edema and the symptoms they cause are frequently underestimated, especially if varicose veins are not present to alert the patient or doctor. The definition, diagnosis, scope, epidemiology, progression and cost of CVD are discussed with evidence to explain how these underestimate the severity of the disease. It is anticipated that once CVD achieves greater recognition this will open up greater opportunities for treatment. These include surgery, endovenous ablation, stenting, compression, venoactive drugs like micronized purifled flavonoid fraction and other drugs such as sulodexide and pentoxifylline. Source

Alastruey J.,Imperial College London
Journal of Biomechanics | Year: 2011

A local estimation of pulse wave speed c, an important predictor of cardiovascular events, can be obtained at arterial locations where simultaneous measurements of blood pressure (P) and velocity (U), arterial diameter (D) and U, flow rate (Q) and cross-sectional area (A), or P and D are available, using the PU-loop, sum-of-squares (Σ 2), lnDU-loop, QA-loop or new D 2P-loop methods. Here, these methods were applied to estimate c from numerically generated P, U, D, Q and A waveforms using a visco-elastic one-dimensional model of the 55 larger human systemic arteries in normal conditions. Theoretical c were calculated from the parameters of the model. Estimates of c given by the loop methods were closer to theoretical values and more uniform within each arterial segment than those obtained using the Σ 2. The smaller differences between estimates and theoretical values were obtained using the D 2P-loop method, with root-mean-square errors (RMSE) smaller than 0.18ms-1, followed by averaging the two c given by the PU- and lnDU-loops (RMSE <2.99ms-1). In general, the errors of the PU-, lnDU- and QA-loops decreased at locations where visco-elastic effects were small and nearby junctions were well-matched for forward-travelling waves. The Σ 2 performed better at proximal locations. © 2010 Elsevier Ltd. Source

Walters J.R.,Imperial College London
Nature reviews. Gastroenterology & hepatology | Year: 2014

Chronic diarrhoea induced by bile acids is common and the underlying mechanisms are linked to homeostatic regulation of hepatic bile acid synthesis by fibroblast growth factor 19 (FGF19). Increasing evidence, including that from several large case series using SeHCAT (selenium homocholic acid taurine) tests for diagnosis, indicates that bile acid diarrhoea (BAD) accounts for a sizeable proportion of patients who would otherwise be diagnosed with IBS. Studies of other approaches for diagnosis of BAD have shown increased bile acid synthesis, increased faecal levels of primary bile acids, dysbiosis and different urinary volatile organic compounds when compared with healthy controls or with other diseases. The role of the ileal hormone FGF19 in BAD has been strengthened: a prospective clinical study has confirmed low FGF19 levels in BAD, and so a test to measure these levels could be developed for diagnosis. In animal models, FGF19 depletion by antibodies produces severe diarrhoea. Bile acids affect colonic function through farnesoid X receptor (FXR) and TGR5 receptors. As well as these effects in the colon, FXR-dependent stimulation of ileal FGF19 production could be a logical mechanism to provide therapeutic benefit in BAD. Further studies of FGF19 in humans hold promise in providing novel treatments for this cause of chronic diarrhoea. Source

Barnes P.J.,Imperial College London
American Journal of Respiratory and Critical Care Medicine | Year: 2013

Theophylline (dimethylxanthine) has been used to treat airway diseases for more than 80 years. It was originally used as a bronchodilator, but the relatively high doses required are associated with frequent side effects, so its use declined as inhaled β2-agonists became more widely used. More recently it has been shown to have antiinflammatory effects in asthma and chronic obstructive pulmonary disease (COPD) at lower concentrations. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase (PDE) 3, but the antiinflammatory effect may be due to inhibition of PDE4 and histone deacetylase-2 activation, resulting in switching off of activated inflammatory genes. Through this mechanism, theophylline also reverses corticosteroid resistance, and this may be of particular value in severe asthma and COPD, wherein histone deacetylase-2 activity is reduced. Theophylline is given systemically (orally as slow-release preparations for chronic treatment and intravenously for acute exacerbations of asthma). Efficacy is related to blood concentrations, which are determined mainly by hepatic metabolism, which may be increased or decreased in several diseases and by concomitant drug therapy. Theophylline is now usually used as an add-on therapy in patients with asthma not well controlled on inhaled corticosteroids with or without long-acting β2-agonists and in patients with COPD with severe disease not controlled by bronchodilator therapy. Side effects are related to plasma concentrations and include nausea, vomiting, and headaches due to PDE inhibition and at higher concentrations to cardiac arrhythmias and seizures due to adenosine A1-receptor antagonism. In the future, low-dose theophylline may be useful in reversing corticosteroid resistance in COPD and severe asthma. Copyright © 2013 by the American Thoracic Society. Source

Scadding G.,Imperial College London
Current allergy and asthma reports | Year: 2014

Allergic rhinitis, particularly seasonal allergic rhinitis, is considered a classic Th2-mediated disease, with important contributions to pathology by interleukins 4, 5 and 13. As such, allergic rhinitis is an excellent model for studying allergic inflammation, with findings potentially relevant to the mechanism of lower airways inflammation seen in allergic asthma. However, recent evidence has revealed roles for additional non-Th2 cytokines in asthma, including IL-17 family cytokines and epithelial-derived cytokines. Additionally, putative roles for epithelial-derived cytokines and innate lymphoid cells have been described in chronic rhinosinusitis with nasal polyps. Here, evidence for the involvement of different cytokines and cytokine groups in allergic rhinitis is considered. Source

Evans A.W.,Imperial College London
Accident Analysis and Prevention | Year: 2011

This paper presents an analysis of fatal train accident rates and trends on Europe's main line railways from 1980 to 2009. The paper uses a new set of data for the European Union together with Norway and Switzerland, assembled partly under the auspices of the European Railway Agency and partly on the author's own account. The estimated overall trend in the number of fatal train collisions and derailments per train-kilometre is -6.3% per year from 1990 to 2009, with a 95% confidence interval of -8.7% to -3.9%. The estimated accident rate in 2009 is 1.35 fatal collisions or derailments per billion train-kilometres, giving an estimated mean number of fatal accidents in 2009 of 6.0. The overall number of fatalities per fatal accident in 1990-2009 is 4.10, with no apparent long term change over time, giving an estimated mean of 24.6 fatalities per year in train collisions and derailments in 2009. There are statistically significant differences in the fatal train accident rates and trends between the different European countries, although the estimates of the rates and trends for many individual countries have wide confidence limits. The distribution of broad causes of accidents appears to have remained unchanged over the long term, so that safety improvements appear to have been across the board, and not focused on any specific cause. The most frequent cause of fatal train collisions and derailments is signals passed at danger. In contrast to fatal train collisions and derailments, the rate per train-kilometre of serious accidents at level crossings remained unchanged in 1990-2009. The immediate causes of most of the serious level crossing accidents are errors or violations by road users. © 2010 Elsevier Ltd. Source

BACKGROUND:: Most anesthetics, particularly intravenous agents such as propofol and etomidate, enhance the actions of the neurotransmitter γ-aminobutyric acid (GABA) at the GABA type A receptor. However, there is no agreement as where anesthetics bind to the receptor. A novel approach would be to identify regions on the receptor that are state-dependent, which would account for the ability of anesthetics to affect channel opening by binding differentially to the open and closed states.METHODS:: The open and closed structures of the GABA type A receptor homologues Gloeobacter ligand–gated ion channel and glutamate-gated chloride channel were compared, and regions in the channels that move on channel opening and closing were identified. Docking calculations were performed to investigate possible binding of propofol to the GABA type A β3 homomer in this region.RESULTS:: A comparison between the open and closed states of the Gloeobacter ligand–gated ion channel and glutamate-gated chloride channel channels identified a region at the top of transmembrane domains 2 and 3 that shows maximum movement when the channels transition between the open and closed states. Docking of propofol into the GABA type A β3 homomer identified two putative binding cavities in this same region, one with a high affinity and one with a lower affinity. Both cavities were adjacent to a histidine residue that has been photolabeled by a propofol analog, and both sites would be disrupted on channel closing.CONCLUSIONS:: These calculations support the conclusion of a recent photolabeling study that propofol acts at a site at the interface between the extracellular and transmembrane domains, close to the top of transmembrane domain 2. © 2015 American Society of Anesthesiologists, Inc. Source

Little M.P.,Imperial College London
Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis | Year: 2010

In this paper we review the evidence for departure from linearity for malignant and non-malignant disease and in the light of this assess likely mechanisms, and in particular the potential role for non-targeted effects.Excess cancer risks observed in the Japanese atomic bomb survivors and in many medically and occupationally exposed groups exposed at low or moderate doses are generally statistically compatible. For most cancer sites the dose-response in these groups is compatible with linearity over the range observed. The available data on biological mechanisms do not provide general support for the idea of a low dose threshold or hormesis. This large body of evidence does not suggest, indeed is not statistically compatible with, any very large threshold in dose for cancer, or with possible hormetic effects, and there is little evidence of the sorts of non-linearity in response implied by non-DNA-targeted effects.There are also excess risks of various types of non-malignant disease in the Japanese atomic bomb survivors and in other groups. In particular, elevated risks of cardiovascular disease, respiratory disease and digestive disease are observed in the A-bomb data. In contrast with cancer, there is much less consistency in the patterns of risk between the various exposed groups; for example, radiation-associated respiratory and digestive diseases have not been seen in these other (non-A-bomb) groups. Cardiovascular risks have been seen in many exposed populations, particularly in medically exposed groups, but in contrast with cancer there is much less consistency in risk between studies: risks per unit dose in epidemiological studies vary over at least two orders of magnitude, possibly a result of confounding and effect modification by well known (but unobserved) risk factors. In the absence of a convincing mechanistic explanation of epidemiological evidence that is, at present, less than persuasive, a cause-and-effect interpretation of the reported statistical associations for cardiovascular disease is unreliable but cannot be excluded. Inflammatory processes are the most likely mechanism by which radiation could modify the atherosclerotic disease process. If there is to be modification by low doses of ionizing radiation of cardiovascular disease through this mechanism, a role for non-DNA-targeted effects cannot be excluded. © 2010 Elsevier B.V. Source

Pellicori P.,Imperial College London
Current Opinion in Cardiology | Year: 2015

PURPOSE OF REVIEW: The number of patients developing heart failure is increasing dramatically, and will likely continue to do so for the next few decades. At least half of the patients with symptoms and signs of heart failure have a normal left ventricular ejection fraction on echocardiography [heart failure with preserved ejection fraction (HFPEF)]. This review updates the current management of patients with HFPEF and summarizes what is in development.RECENT FINDINGS: Many different pathophysiologies may result in HFPEF. No single imaging measure may reliably identify cardiac dysfunction, but plasma concentrations of natriuretic peptides, reflecting the final pathway of congestion, appear to. Natriuretic peptides are now an essential part of the diagnostic process and are increasingly used to select patients to be enrolled in clinical trials. No therapeutic intervention has unequivocally been shown to modify the natural history of HFPEF, although several improve symptoms and functional capacity, which are important targets in this population. The failure of many clinical trials may reflect the inclusion of patients who are at low risk of cardiovascular events or the diverse pathophysiology of HFPEF. When patients are congested (i.e. have elevated plasma concentrations of natriuretic peptides) a diagnosis of HFPEF can be made with some confidence, the patients will be at increased cardiovascular risk and treatments aimed at correcting congestion will probably be effective. Selection of treatment to target a specific underlying pathophysiology is an alternative, relatively untried approach.SUMMARY: Further clinical trials will provide new insights into the pathophysiology of this complex disease and, hopefully, identify therapies that also improve outcome. © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins Source

Shanahan M.,Imperial College London
Chaos | Year: 2010

A system of symmetrically coupled identical oscillators with phase lag is presented, which is capable of generating a large repertoire of transient (metastable) "chimera" states in which synchronization and desynchronization coexist. The oscillators are organized into communities, such that each oscillator is connected to all its peers in the same community and to a subset of the oscillators in other communities. Measures are introduced for quantifying metastability, the prevalence of chimera states, and the variety of such states a system generates. By simulation, it is shown that each of these measures is maximized when the phase lag of the model is close, but not equal, to π/2. The relevance of the model to a number of fields is briefly discussed with particular emphasis on brain dynamics. © 2010 American Institute of Physics. Source

Umasunthar T.,Imperial College London
Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology | Year: 2013

Food allergy is a common cause of anaphylaxis, but the incidence of fatal food anaphylaxis is not known. The aim of this study was to estimate the incidence of fatal food anaphylaxis for people with food allergy and relate this to other mortality risks in the general population. We undertook a systematic review and meta-analysis, using the generic inverse variance method. Two authors selected studies by consensus, independently extracted data and assessed the quality of included studies using the Newcastle-Ottawa assessment scale. We searched Medline, Embase, PsychInfo, CINAHL, Web of Science, LILACS or AMED, between January 1946 and September 2012, and recent conference abstracts. We included registries, databases or cohort studies which described the number of fatal food anaphylaxis cases in a defined population and time period and applied an assumed population prevalence rate of food allergy. We included data from 13 studies describing 240 fatal food anaphylaxis episodes over an estimated 165 million food-allergic person-years. Study quality was mixed, and there was high heterogeneity between study results, possibly due to variation in food allergy prevalence and data collection methods. In food-allergic people, fatal food anaphylaxis has an incidence rate of 1.81 per million person-years (95%CI 0.94, 3.45; range 0.63, 6.68). In sensitivity analysis with different estimated food allergy prevalence, the incidence varied from 1.35 to 2.71 per million person-years. At age 0-19, the incidence rate is 3.25 (1.73, 6.10; range 0.94, 15.75; sensitivity analysis 1.18-6.13). The incidence of fatal food anaphylaxis in food-allergic people is lower than accidental death in the general European population. Fatal food anaphylaxis for a food-allergic person is rarer than accidental death in the general population. © 2013 The Authors Clinical & Experimental Allergy Published by John Wiley & Sons Ltd. Source

Habgood M.,Imperial College London
Crystal Growth and Design | Year: 2013

Cocrystals offer two novel variants on the classic salt formation method of chiral resolution. Diastereomeric cocrystal pairs are directly analogous to salts but without the requirement for proton transfer. Conversely, a coformer that cocrystallizes with one enantiomer but not the other (enantiospecific cocrystallization) has recently been shown to give high enantiomeric yield. For either variant an understanding of intermolecular interactions is vital. In this study computational crystal structure prediction (CSP) is applied to three recently reported examples: levetiracetam with mandelic acid and with tartaric acid, which display enantiospecific cocrystallization, and tartaric acid with malic acid, which forms a diastereomeric cocrystal pair. The ability of CSP techniques to predict the experimental cocrystal structures is demonstrated. The chirally selective interactions are determined using the unique capabilities of CSP, with reference to alternative structures for each cocrystal system, including the hypothetical diastereomeric twins of the levetiracetam cocrystals. In each case, chiral selectivity can be described in terms of the dominant R22(8) dimer's response to the change in enantiomer. It is concluded that when designing a coformer for chiral resolution a predilection toward a single, orientationally restrictive intermolecular motif, with minimal ability to form alternative motifs, is the best strategy. © 2013 American Chemical Society. Source

Strelkowa N.,Imperial College London | Lassig M.,University of Cologne
Genetics | Year: 2012

The seasonal influenza A virus undergoes rapid evolution to escape human immune response. Adaptive changes occur primarily in antigenic epitopes, the antibody-binding domains of the viral hemagglutinin. This process involves recurrent selective sweeps, in which clusters of simultaneous nucleotide fixations in the hemagglutinin coding sequence are observed about every 4 years. Here, we show that influenza A (H3N2) evolves by strong clonal interference. This mode of evolution is a red queen race between viral strains with different beneficial mutations. Clonal interference explains and quantifies the observed sweep pattern: we find an average of at least one strongly beneficial amino acid substitution per year, and a given selective sweep has three to four driving mutations on average. The inference of selection and clonal interference is based on frequency time series of single-nucleotide polymorphisms, which are obtained from a sample of influenza genome sequences over 39 years. Our results imply that mode and speed of influenza evolution are governed not only by positive selection within, but also by background selection outside antigenic epitopes: immune adaptation and conservation of other viral functions interfere with each other. Hence, adapting viral proteins are predicted to be particularly brittle. We conclude that a quantitative understanding of influenza's evolutionary and epidemiological dynamics must be based on all genomic domains and functions coupled by clonal interference. © 2012 by the Genetics Society of America. Source

Rosindell J.,University of Leeds | Rosindell J.,University of Idaho | Phillimore A.B.,Imperial College London
Ecology Letters | Year: 2011

Islands acquire species through immigration and speciation. Models of island biogeography should capture both processes; however quantitative island biogeography theory has either neglected speciation or treated it unrealistically. We introduce a model where the dominance of immigration on small and near islands gives way to an increasing role for speciation as island area and isolation increase. We examine the contribution of immigration and speciation to the avifauna of 35 archipelagoes and find, consistent with our model, that the zone of radiation comprises two regions: endemic species diverged from mainland sister-species at intermediate isolation and from insular sister-species at higher levels of isolation. Our model also predicts species-area curves in accord with existing research and makes new predictions about species ages and abundances. We argue that a paucity of data and theory on species abundances on isolated islands highlights the need for island biogeography to be reconnected with mainstream ecology. © 2011 Blackwell Publishing Ltd/CNRS. Source

Bures J.,Imperial College London
Angewandte Chemie - International Edition | Year: 2016

A graphical analysis to elucidate the order in catalyst is presented. This analysis uses a normalized time scale, t [cat]T n, to adjust entire reaction profiles constructed with concentration data. The method is fast and simple to perform because it directly uses the concentration data, therefore avoiding the data handling that is usually required to extract rates. Compared to methods that use rates, the normalized time scale analysis requires fewer experiments and minimizes the effects of experimental errors by using information on the entire reaction profile. A graphical analysis to elucidate the order in catalyst uses a normalized time scale, t [cat]T n, to adjust entire reaction profiles constructed with concentration data. Compared to methods that use rates, the normalized time scale analysis requires fewer experiments and minimizes the effects of experimental errors by using information on the entire reaction profile. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Nienaber C.A.,University of Rostock | Powell J.T.,Imperial College London
European Heart Journal | Year: 2012

Acute aortic syndrome (AAS) is a modern term to describe interrelated emergency aortic conditions with similar clinical characteristics and challenges. These conditions include aortic dissection, intramural haematoma (IMH), and penetrating atherosclerotic ulcer (PAU and aortic rupture); trauma to the aorta with intimal laceration may also be considered. The common denominator of AAS is disruption of the media layer of the aorta with bleeding within IMH, along the aortic media resulting in separation of the layers of the aorta (dissection), or transmurally through the wall in the case of ruptured PAU or trauma. Population-based studies suggest that the incidence of acute dissection ranges from 2 to 3.5 cases per 100 000 person-years; hypertension and a variety of genetic disorders with altered connective tissues are the most prevalent risk conditions. Patients with AAS often present in a similar fashion, regardless of the underlying condition of dissection, IMH, PAU, or contained aortic rupture. Pain is the most commonly presenting symptom of acute aortic dissection and should prompt immediate attention including diagnostic imaging modalities (such as multislice computed tomography, transoesophageal ultrasound, or magnetic resonance imaging). Prognosis is clearly related to undelayed diagnosis and appropriate surgical repair in the case of proximal involvement of the aorta; affection of distal segments of the aorta may call for individualized therapeutic approaches favouring endovascular in the presence of malperfusion or imminent rupture, or medical management. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2011. Source

Donos A.,Imperial College London | Hartnoll S.A.,Stanford University
Nature Physics | Year: 2013

Interaction-driven charge localization across a quantum phase transition involves a fundamental rearrangement of the low-energy degrees of freedom. This fact challenges weakly interacting quasiparticle descriptions of the physics. The canonical example of such localization is the Mott transition. Here, we present a localization mechanism distinct from 'Mottness', which employs strong interactions in an essential way. Our mechanism allows anisotropic localization: phases can arise that are insulating in some directions and metallic in others. The central observation is that localization occurs if an operator that breaks translation invariance, a 'generalized Umklapp' operator, becomes relevant in the effective low-energy theory. This does not occur at weak coupling. We realize such localization in a strongly interacting theory described by means of the holographic correspondence. Our model captures key features of metal-insulator transitions including major spectral weight transfer and bad (incoherent) metallic behaviour in the vicinity of the transition. The localized phase has a power law gap in the optical conductivity. © 2013 Macmillan Publishers Limited. Source

Silver M.,Imperial College London
Statistical applications in genetics and molecular biology | Year: 2012

Where causal SNPs (single nucleotide polymorphisms) tend to accumulate within biological pathways, the incorporation of prior pathways information into a statistical model is expected to increase the power to detect true associations in a genetic association study. Most existing pathways-based methods rely on marginal SNP statistics and do not fully exploit the dependence patterns among SNPs within pathways.We use a sparse regression model, with SNPs grouped into pathways, to identify causal pathways associated with a quantitative trait. Notable features of our "pathways group lasso with adaptive weights" (P-GLAW) algorithm include the incorporation of all pathways in a single regression model, an adaptive pathway weighting procedure that accounts for factors biasing pathway selection, and the use of a bootstrap sampling procedure for the ranking of important pathways. P-GLAW takes account of the presence of overlapping pathways and uses a novel combination of techniques to optimise model estimation, making it fast to run, even on whole genome datasets.In a comparison study with an alternative pathways method based on univariate SNP statistics, our method demonstrates high sensitivity and specificity for the detection of important pathways, showing the greatest relative gains in performance where marginal SNP effect sizes are small. Source

Berman D.S.,Queen Mary, University of London | Lee K.,Imperial College London | Lee K.,Sogang University
Nuclear Physics B | Year: 2014

Previous constructions of supersymmetry for double field theory have relied on the so-called strong constraint. In this paper, the strong constraint is relaxed and the theory is shown to possess supersymmetry once the generalised Scherk-Schwarz reduction is imposed. The equivalence between the generalised Scherk-Schwarz reduced theory and the gauged double field theory is then examined in detail for the supersymmetric theory. As a biproduct we write the generalised Killing spinor equations for the supersymmetric double field theory. © 2014 Elsevier B.V. Source

Foster K.R.,University of Oxford | Bell T.,Imperial College London
Current Biology | Year: 2012

Microbial cells secrete numerous enzymes, scavenging molecules, and signals that can promote the growth and survival of other cells around them [1-4]. This observation is consistent with the evolution of cooperation within species [5], and there is now an increasing emphasis on the importance of cooperation between different microbial species [4, 6]. We lack, however, a systematic test of the importance of mutually positive interactions between different species, which is vital for assessing the commonness and importance of cooperative evolution in natural communities. Here, we study the extent of mutually positive interaction among bacterial strains isolated from a common aquatic environment. Using data collected from two independent experiments evaluating community productivity across diversity gradients, we show that (1) in pairwise species combinations, the great majority of interactions are net negative and (2) there is no evidence that strong higher-order positive effects arise when more than two species are mixed together. Our data do not exclude the possibility of positive effects in one direction where one species gains at the expense of another, i.e., predator-prey-like interactions. However, these do not constitute cooperation and our analysis suggests that the typical result of adaptation to other microbial species will be competitive, rather than cooperative, phenotypes. © 2012 Elsevier Ltd. All rights reserved. Source

Barnes P.J.,Imperial College London
Trends in Pharmacological Sciences | Year: 2010

Current therapy for asthma with inhaled corticosteroids and long-acting inhaled β2-agonists is highly effective, safe and relatively inexpensive, but for many patients, their disease remains poorly controlled. Most advances in asthma therapy have occurred through improving these drug classes, and a major developmental hurdle is to improve existing drug classes. The major unmet needs include better treatment of severe asthma, and curative therapies for mild to moderate asthma. Many new treatments are specific, targeting a single mediator or receptor, and are unlikely to have a major clinical effect, although they might be effective in specific asthma phenotypes. Drugs with more widespread effects, such as kinase inhibitors, might be more effective but have a greater risk of side effects. New treatments targeting the underlying allergic/immune process would treat concomitant allergic diseases. Improved immunotherapy approaches have the prospect of disease modification, although prospects for a cure are currently remote. The most promising therapeutic developments for asthma are discussed in this review. © 2010 Elsevier Ltd. Source

Puri B.K.,Imperial College London
Expert Review of Neurotherapeutics | Year: 2010

Several important progressive brain changes occur in schizophrenia. Continuous progressive brain tissue decreases and lateral ventricular volume increases in chronically ill patients, up to at least 20 years after their first symptoms. The total duration of psychosis may be negatively associated with the grey matter volume change, and positively associated with the volume change of each of the lateral ventricles and the third ventricle. There are progressive frontal changes in males with adolescent-onset psychosis. Ultra high-risk patients who subsequently develop psychosis and first-episode psychosis patients develop significant grey matter reduction in the planum polare, planum temporale and caudal region; a progressive process in the superior temporal gyrus may precede the first expression of florid psychosis. The rate of decline in the sizes of the putamen and corpus callosum is greater in patients with a poor outcome compared to those with a good-outcome. In addition to describing these phenomena, their potential causes are discussed. © 2010 Expert Reviews Ltd. Source

Ramasamy A.,Imperial College London
The Journal of bone and joint surgery. American volume | Year: 2013

Improvements in protection and medical treatments have resulted in increasing numbers of modern-warfare casualties surviving with complex lower-extremity injuries. To our knowledge, there has been no prior analysis of foot and ankle blast injuries as a result of improvised explosive devices (IEDs). The aims of this study were to report the pattern of injury and determine which factors are associated with a poor clinical outcome. U.K. service personnel who had sustained lower leg injuries following an under-vehicle explosion from January 2006 to December 2008 were identified with the use of a prospective trauma registry. Patient demographics, injury severity, the nature of the lower leg injury, and the type of clinical management were recorded. Clinical end points were determined by (1) the need for amputation and (2) ongoing clinical symptoms. Sixty-three U.K. service personnel (eighty-nine injured limbs) with lower leg injuries from an explosion were identified. Fifty-one percent of the casualties sustained multisegmental injuries to the foot and ankle. Twenty-six legs (29%) required amputation, with six of them amputated because of chronic pain eighteen months following injury. Regression analysis revealed that hindfoot injuries, open fractures, and vascular injuries were independent predictors of amputation. At the time of final follow-up, sixty-six (74%) of the injured limbs had persisting symptoms related to the injury, and only nine (14%) of the service members were fit to return to their preinjury duties. This study demonstrates that foot and ankle injuries from IEDs are associated with a high amputation rate and frequently with a poor clinical outcome. Although not life-threatening, they remain a source of long-term morbidity in an active population. Source

Taylor P.C.,Imperial College London
Current Opinion in Pharmacology | Year: 2010

Tumor necrosis factor-alpha (TNF) has been unequivocally validated as a therapeutic target in a number of immune-mediated inflammatory disorders (IMIDs). There is now increasing choice of biologic agents within the class all of which successfully neutralize sTNF. But approaches to TNF inhibition differ and currently include mAbs (infliximab, adalimumab, and golimumab), either chimeric or human in sequence, a PEGylated Fab' fragment (certolizumab), and an IgG1-TNFR2 fusion protein (etanercept). It is emerging that the pharmacological properties of these three anti-TNF subtypes differ with respect to Fc function, binding of tmTNF and the possible consequences of this, as well as the ability to form complexes. The mode of administration of each agent, clearance and the local tissue concentrations achieved may also confer unique characteristics of relevance with respect to efficacy and safety. © 2010. Source

Barnes P.J.,Imperial College London
Immunological Reviews | Year: 2011

Allergic inflammation is due to a complex interplay between several inflammatory cells, including mast cells, basophils, lymphocytes, dendritic cells, eosinophils, and sometimes neutrophils. These cells produce multiple inflammatory mediators, including lipids, purines, cytokines, chemokines, and reactive oxygen species. Allergic inflammation affects target cells, such as epithelial cells, fibroblasts, vascular cells, and airway smooth muscle cells, which become an important source of inflammatory mediators. Sensory nerves are sensitized and activated during allergic inflammation and produce symptoms. Allergic inflammatory responses are orchestrated by several transcription factors, particularly NF-κB and GATA3. Inflammatory genes are also regulated by epigenetic mechanisms, including DNA methylation and histone modifications. There are several endogenous anti-inflammatory mechanisms, including anti-inflammatory lipids and cytokines, which may be defective in allergic disease, thus amplifying and perpetuating the inflammation. Better understanding of the pathophysiology of allergic inflammation has identified new therapeutic targets but developing effective novel therapies has been challenging. Corticosteroids are highly effective with a broad spectrum of anti-inflammatory effects, including epigenetic modulation of the inflammatory response and suppression of GATA3. © 2011 John Wiley & Sons A/S. Source

Norman P.E.,University of Western Australia | Powell J.T.,Imperial College London
Circulation Research | Year: 2014

Vitamin D plays a classical hormonal role in skeletal health by regulating calcium and phosphorus metabolism. Vitamin D metabolites also have physiological functions in nonskeletal tissues, where local synthesis influences regulatory pathways via paracrine and autocrine mechanisms. The active metabolite of vitamin D, 1α,25-dihydroxyvitamin D, binds to the vitamin D receptor that regulates numerous genes involved in fundamental processes of potential relevance to cardiovascular disease, including cell proliferation and differentiation, apoptosis, oxidative stress, membrane transport, matrix homeostasis, and cell adhesion. Vitamin D receptors have been found in all the major cardiovascular cell types including cardiomyocytes, arterial wall cells, and immune cells. Experimental studies have established a role for vitamin D metabolites in pathways that are integral to cardiovascular function and disease, including inflammation, thrombosis, and the renin-angiotensin system. Clinical studies have generally demonstrated an independent association between vitamin D deficiency and various manifestations of degenerative cardiovascular disease including vascular calcification. However, the role of vitamin D supplementation in the management of cardiovascular disease remains to be established. This review summarizes the clinical studies showing associations between vitamin D status and cardiovascular disease and the experimental studies that explore the mechanistic basis for these associations. © 2014 American Heart Association, Inc. Source

Manfredi S.,University of Naples Federico II | Manfredi S.,Imperial College London
IEEE Wireless Communications | Year: 2014

Rapid advances in Information and Communications Technologies are enabling the wide diffusion of healthcare systems which allow a continuous remote patient monitoring and diagnostics by doctors. The need for pervasive and ubiquitous healthcare services has accelerated the development of heterogeneous communication architectures that integrate one or more different types of wired and wireless network technologies such as those used in the Internet, and in cellular, wireless body networks, and ad hoc networks. However, these modern healthcare systems have established some additional critical requirements and challenges, compared to traditional wireless networks, such as reliability and the timely access to diagnostic information without failure. The main aim of this article is to propose a healthcare traffic control over the modern heterogeneous wireless network to avoid congestion phenomena and guarantee QoS (Quality of Service) in terms of service reliability and responsiveness. First, a proportional fair allocation control strategy at each healthcare terminal device/router is implemented to regulate the rate of data flow proportionally to the information priority. The priority can be related to both the bandwidth requirement for the reliable communication of a vital signal and to the level of emergency in specific acute care, clinical disease and outbreak/disaster situations. Secondly, we present a congestion control based on the adaptive fairness criterion that can deal with differentiated and dynamic healthcare scenarios. A simulator environment has been built to validate the effectiveness of the proposed approaches. © 2014 IEEE. Source

Fernando R.J.,Imperial College London
The Cochrane database of systematic reviews | Year: 2013

Anal sphincter injury during childbirth - obstetric anal sphincter injuries (OASIS) - are associated with significant maternal morbidity including perineal pain, dyspareunia (painful sexual intercourse) and anal incontinence, which can lead to psychological and physical sequelae. Many women do not seek medical attention because of embarrassment. The two recognised methods for the repair of damaged external anal sphincter (EAS) are end-to-end (approximation) repair and overlap repair. To compare the effectiveness of overlap repair versus end-to-end repair following OASIS in reducing subsequent anal incontinence, perineal pain, dyspareunia and improving quality of life. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2013) and reference lists of retrieved studies. Randomised controlled trials comparing different techniques of immediate primary repair of EAS following OASIS. Trial quality was assessed independently by all authors. Six eligible trials, of variable quality, involving 588 women, were included. There was considerable heterogeneity in the outcome measures, time points and reported results. Meta-analyses showed that there was no statistically significant difference in perineal pain (risk ratio (RR) 0.08, 95% confidence interval (CI) 0.00 to 1.45, one trial, 52 women), dyspareunia (average RR 0.77, 95% CI 0.48 to 1.24, two trials, 151 women), flatus incontinence (average RR 1.14, 95% CI 0.58 to 2.23, three trials, 256 women) between the two repair techniques at 12 months. However, it showed a statistically significant lower incidence of faecal urgency (RR 0.12, 95% CI 0.02 to 0.86, one trial, 52 women), and lower anal incontinence score (standardised mean difference (SMD) -0.70, 95% CI -1.26 to -0.14, one trial, 52 women) in the overlap group. The overlap technique was also associated with a statistically significant lower risk of deterioration of anal incontinence symptoms over 12 months (RR 0.26, 95% CI 0.09 to 0.79, one trial, 41 women). There was no significant difference in quality of life. At 36 months follow-up, there was no difference in flatus incontinence (average RR 1.12, 95% CI 0.63 to 1.99, one trial, 68 women) or faecal incontinence (average RR 1.01, 95% CI 0.34 to 2.98, one trial, 68 women). The data available show that at one-year follow-up, immediate primary overlap repair of the external anal sphincter compared with immediate primary end-to-end repair appears to be associated with lower risks of developing faecal urgency and anal incontinence symptoms. At the end of 36 months there appears to be no difference in flatus or faecal incontinence between the two techniques. However, since this evidence is based on only two small trials, more research evidence is needed in order to confirm or refute these findings. Source

Brooks D.J.,Imperial College London
Movement Disorders | Year: 2010

In this review, in vivo patterns of structural, metabolic, and neurotransmitter binding changes revealed by imaging in both symptomatic Parkinson's disease (PD) and at-risk subjects are compared with those predicted at different Braak stages. It is concluded that the dysfunction revealed by imaging in PD is only partially in line with the sequential ascending topography of Lewy body pathology reported by Braak, suggesting that neurons in different brain regions are likely to be selectively vulnerable to the presence of intracellular synuclein aggregates. © 2010 Movement Disorder Society. Source

Ozaki R.,Imperial College London
Business Strategy and the Environment | Year: 2011

This paper investigates what encourages consumers to adopt a green electricity tariff. When people decide to adopt an innovation, such as green electricity, they consider not only functionality, usability, costs and intended outcomes, but also what the innovation means to them, for example, the way it reflects their identity, image, memberships, values and norms. The study reviews the theoretical frameworks of innovation adoption and consumption, and cognitive and normative behaviour, relevant to consumer adoption of pro-environmental innovations, and develops a research framework. Through focus group discussions, a questionnaire survey with 103 respondents and an interview with 10 people, the study finds that consumers sympathetic to environmental issues do not necessarily adopt green electricity. This is due to lack of strong social norms and personal relevance, inconvenience of switching, uncertainty about the quality of green electricity and lack of accurate information. The implications of these findings for strategy, policy and future research are explored. © 2009 John Wiley & Sons, Ltd and ERP Environment. Source

Marin D.,Imperial College London
Seminars in Hematology | Year: 2010

Imatinib is remarkably effective in treating newly diagnosed patients with chronic myeloid leukemia (CML) in chronic phase. However, at 5 years more than one third of the patients have abandoned the medication on account of side effects, lack of efficacy, or progression. Here we review the current results with imatinib, the prognostic factors for response, and issues associated with long-term treatment with imatinib such as pregnancy, adherence to therapy, and complete molecular responses. © 2010 Elsevier Inc. Source

Muller-Wodarg I.C.F.,Imperial College London
Nature Physics | Year: 2016

Waves are ubiquitous phenomena found in oceans and atmospheres alike. From the earliest formal studies of waves in the Earth’s atmosphere to more recent studies on other planets, waves have been shown to play a key role in shaping atmospheric bulk structure, dynamics and variability. Yet, waves are difficult to characterize as they ideally require in situ measurements of atmospheric properties that are difficult to obtain away from Earth. Thus, we have incomplete knowledge of atmospheric waves on planets other than our own, and we are thereby limited in our ability to understand and predict planetary atmospheres. Here we report the first ever in situ observations of atmospheric waves in Venus’s thermosphere (130–140 km) at high latitudes (71.5°–79.0°). These measurements were made by the Venus Express Atmospheric Drag Experiment (VExADE) during aerobraking from 24 June to 11 July 2014. As the spacecraft flew through Venus’s atmosphere, deceleration by atmospheric drag was sufficient to obtain from accelerometer readings a total of 18 vertical density profiles. We infer an average temperature of T = 114 ± 23 K and find horizontal wave-like density perturbations and mean temperatures being modulated at a quasi-5-day period. © 2016 Nature Publishing Group Source

Peters R.,Imperial College London
Experimental Gerontology | Year: 2012

The success of the ageing global population brings with it a growth in the number of dementia sufferers. Older adults are at highest risk of dementia and are likely to manifest both vascular and Alzheimer's pathology. Blood pressure also changes with ageing and there is evidence linking high blood pressure in midlife to an increased risk of later dementia. Data from later life is sparser. A number of intervention trials have been carried out with antihypertensives and have shown mixed results with regard to cognitive and dementia outcomes (both dementia overall and of vascular and Alzheimer's types). Meta-analyses have in general not found an association between blood pressure lowering and reduced dementia incidence, although the number of cases reported in the placebo controlled trials is invariably lower in the actively treated group. Systematic reviews and meta-analyses have also been published with regard to smoking and alcohol use and incident dementia. Despite mixed reports, overall smoking was associated with an increased risk of later dementia and alcohol with a 'U' or 'J' shaped relationship. Following the systematic reviews subsequent publications tend to report similar findings. The literature in this area suffers from differing populations, lengths of follow up and assessments of both risk factor and outcome. However, at present, maintenance of cognitive function would seem to be best served by treating cardiovascular risk factors in accordance with current guidelines, controlling blood pressure, reducing smoking and if consuming alcohol doing so in moderation.This review will concentrate on the prevention of dementia and attempt to provide an overview of the evidence relating to vascular related dementia and the potential risk factors of hypertension, alcohol use and smoking behaviour. © 2012 Elsevier Inc. Source

Boyle J.J.,Imperial College London | Boyle J.J.,Center for Experimental and Translational Medicine
Current Opinion in Lipidology | Year: 2012

PURPOSE OF REVIEW: Several studies have recently shown that haemoglobin drives a novel macrophage subset that is protected from foam cell formation. RECENT FINDINGS: In a previously overlooked area, two centres have independently shown that heme and haemoglobin drive an atheroprotective macrophage subset. We compare and contrast the approaches and findings of the laboratories and discuss some of the underlying biology and implications, concentrating on the aspects of lipidological relevance. SUMMARY: Treatments based on direct heme-mimetics or other agonists of this pathway have enormous potential for linked antioxidant protection via heme oxygenase 1 and reduced foam cell formation via liver X receptor, a potent combination for treating atherosclerosis. © 2012 Wolters Kluwer Health | Lippincott Williams &Wilkins. Source

Kamaly N.,Imperial College London
Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging | Year: 2010

PURPOSE: Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was utilized in postmortem imaging of gadolinium (Gd) spatial distribution in a mouse tumor model postadministration of PEGylated Gd liposomal nanoparticles. PROCEDURES: PEGylated liposomal nanoparticles were formulated using a paramagnetic lipid incorporating Gd, in addition to a fluorescent lipid, and injected intravenously into Balb/C nude mice bearing IGROV-1 tumors. At postinjection (2 h), the tumors and selective organs were imaged by magnetic resonance imaging (MRI) and, after excision, by histology and LA-ICP-MS. RESULTS: The presence of Gd within tumor tissue was confirmed by LA-ICP-MS and when correlated to histology was found to be prevalent in regions of higher vascularity. The presence of Gd in the kidneys was also confirmed. CONCLUSIONS: We have demonstrated, in a novel manner, the use of LA-ICP-MS for the spatial detection of Gd in tumor tissue. LA-ICP-MS is valuable in providing spatio-specific information of MRI contrast agents and more importantly Gd in tumor tissue. Source

Toni F.,Imperial College London
Argument and Computation | Year: 2014

We give an introductory tutorial to assumption-based argumentation (referred to as ABA)-a form of argumentation where arguments and attacks are notions derived from primitive notions of rules in a deductive system, assumptions and contraries thereof. ABA is equipped with different semantics for determining winning sets of assumptions and-interchangeably and equivalently-winning sets of arguments. It is also equipped with a catalogue of computational techniques to determine whether given conclusions can be supported by a winning set of arguments. These are in the form of disputes between (fictional) proponent and opponent players, provably correct w.r.t. the semantics. Albeit simple, ABA is powerful in that it can be used to represent and reason with a number of problems in AI and beyond: non-monotonic reasoning, preferences, decisions. While doing so, it encompasses the expressive and computational needs of these problems while affording the transparency and explanatory power of argumentation. © 2014 Taylor and Francis. Source

Acetaminophen (APAP, paracetamol, N-acetyl-p-aminophenol) is a widely used analgesic that is safe at therapeutic doses but is a major cause of acute liver failure (ALF) following overdose. APAP-induced hepatotoxicity is related to the formation of an electrophilic reactive metabolite, N-acetyl-p-benzoquinone imine (NAPQI), which is detoxified through conjugation with reduced glutathione (GSH). One method that has been applied to study APAP metabolism and hepatotoxicity is that of metabolic phenotyping, which involves the study of the small molecule complement of complex biological samples. This approach involves the use of high-resolution analytical platforms such as NMR spectroscopy and mass spectrometry to generate information-rich metabolic profiles that reflect both genetic and environmental influences and capture both endogenous and xenobiotic metabolites. Data modeling and mining and the subsequent identification of panels of candidate biomarkers are typically approached with multivariate statistical tools. We review the application of multi-platform metabolic profiling for the study of APAP metabolism in both in vivo models and humans. We also review the application of metabolic profiling for the study of endogenous metabolic pathway perturbations in response to APAP hepatotoxicity, with a particular focus on metabolites involved in the biosynthesis of GSH and those that reflect mitochondrial function such as long-chain acylcarnitines. Taken together, this body of work sheds much light on the mechanism of APAP-induced hepatotoxicity and provides candidate biomarkers that may prove of translational relevance for improved stratification of APAP-induced ALF. © 2014 Informa Healthcare USA, Inc. All rights reserved. Source

In this review, I outline the indirect evidence for the formation of singlet oxygen (1O2) obtained from experiments with the isolated PSII reaction center complex. I also review the methods we used to measure singlet oxygen directly, including luminescence at 1,270 nm, both steady state and time resolved. Other methods we used were histidine-catalyzed molecular oxygen uptake (enabling 1O2 yield measurements), and dye bleaching and difference absorption spectroscopy to identify where quenchers of 1O2 can access this toxic species. We also demonstrated the protective behavior of carotenoids bound within Chl-protein complexes which bring about a substantial amount of 1O2 quenching within the reaction center complex. Finally, I describe how these techniques have been used and expanded in research on photoinhibition and on the role of 1O2 as a signaling molecule in instigating cellular responses to various stress factors. I also discuss the current views on the role of 1O2 as a signaling molecule and the distance it might be able to travel within cells. © 2014 The Author 2014. Source

Walters J.R.F.,Imperial College London
Nature Reviews Gastroenterology and Hepatology | Year: 2014

Chronic diarrhoea induced by bile acids is common and the underlying mechanisms are linked to homeostatic regulation of hepatic bile acid synthesis by fibroblast growth factor 19 (FGF19). Increasing evidence, including that from several large case series using SeHCAT (selenium homocholic acid taurine) tests for diagnosis, indicates that bile acid diarrhoea (BAD) accounts for a sizeable proportion of patients who would otherwise be diagnosed with IBS. Studies of other approaches for diagnosis of BAD have shown increased bile acid synthesis, increased faecal levels of primary bile acids, dysbiosis and different urinary volatile organic compounds when compared with healthy controls or with other diseases. The role of the ileal hormone FGF19 in BAD has been strengthened: a prospective clinical study has confirmed low FGF19 levels in BAD, and so a test to measure these levels could be developed for diagnosis. In animal models, FGF19 depletion by antibodies produces severe diarrhoea. Bile acids affect colonic function through farnesoid X receptor (FXR) and TGR5 receptors. As well as these effects in the colon, FXR-dependent stimulation of ileal FGF19 production could be a logical mechanism to provide therapeutic benefit in BAD. Further studies of FGF19 in humans hold promise in providing novel treatments for this cause of chronic diarrhoea. © 2014 Macmillan Publishers Limited. All rights reserved. Source

Lenhard B.,Imperial College London | Lenhard B.,Clinical Science Center | Lenhard B.,University of Bergen | Sandelin A.,Copenhagen University | Carninci P.,RIKEN
Nature Reviews Genetics | Year: 2012

Promoters are crucial for gene regulation. They vary greatly in terms of associated regulatory elements, sequence motifs, the choice of transcription start sites and other features. Several technologies that harness next-generation sequencing have enabled recent advances in identifying promoters and their features, helping researchers who are investigating functional categories of promoters and their modes of regulation. Additional features of promoters that are being characterized include types of histone modifications, nucleosome positioning, RNA polymerase pausing and novel small RNAs. In this Review, we discuss recent findings relating to metazoan promoters and how these findings are leading to a revised picture of what a gene promoter is and how it works. © 2012 Macmillan Publishers Limited. All rights reserved. Source

Purohit A.,Imperial College London | Foster P.A.,Center for Endocrinology
Journal of Endocrinology | Year: 2012

Estrogens and androgens are instrumental in the maturation of many hormone-dependent cancers. Consequently, the enzymes involved in their synthesis are cancer therapy targets. One such enzyme, steroid sulfatase (STS), hydrolyses estrone sulfate, and dehydroepiandrosterone sulfate to estrone and dehydroepiandrosterone respectively. These are the precursors to the formation of biologically active estradiol and androstenediol. This review focuses on three aspects of STS inhibitors: 1) chemical development, 2) biological activity, and 3) clinical trials. The aim is to discuss the importance of estrogens and androgens in many cancers, the developmental history of STS inhibitor synthesis, the potency of these compounds in vitro and in vivo and where we currently stand in regards to clinical trials for these drugs. STS inhibitors are likely to play an important future role in the treatment of hormone-dependent cancers. Novel in vivomodels have been developed that allowpre-clinical testing of inhibitors and the identification of lead clinical candidates. Phase I/II clinical trials in postmenopausal women with breast cancer have been completed and other trials in patients with hormone-dependent prostate and endometrial cancer are currently active. Potent STS inhibitors should become therapeutically valuable in hormone-dependent cancers and other non-oncological conditions. © 2012 Society for Endocrinology. Source

Grimm S.,Imperial College London
Biochimica et Biophysica Acta - Molecular Cell Research | Year: 2012

When cellular organelles communicate bad things can happen. Recent findings uncovered that the junction between the endoplasmic reticulum (ER) and the mitochondria holds a crucial role for cell death regulation. Not only does this locale connect the two best-known organelles in apoptosis, numerous regulators of cell death are concentrated at this spot, providing a terrain for intense signal transfers. Ca 2+ is the most prominent signalling factor that is released from the ER and, at high concentration, mediates the transfer of an apoptosis signal to mitochondria as the executioner organelle for cell death. An elaborate array of checks and balances is fine-tuning this process including Bcl-2 family members. Moreover, MAMs, "mitochondria-associated membranes", are distinct membrane sections at the ER that are in close contact with mitochondria and have been found to exchange lipids and lipid-derived molecules such as ceramide for apoptosis induction. Recent work has also described a reverse transfer of apoptosis signals, from mitochondria to the ER, via cytochrome c release and prolonged IP 3R opening or through the mitochondrial fission factor Fis1 and Bap31 at the ER, which form the ARCosome, a novel caspase-activation complex. © 2011 Elsevier B.V. Source

Dumas M.-E.,Imperial College London
Molecular BioSystems | Year: 2012

The characterization of the metabolome has rapidly evolved over two decades, from early developments in analytical chemistry to systems biology. Metabolites and small molecules are not independent; they are organized in biochemical pathways and in a wider metabolic network, which is itself dependent on various genetic and signaling networks for its regulation. Recent advances in genomics, transcriptomics, proteomics and metabolomics have been matched by the development of publicly available repositories, which have helped shaping a new generation of integrative studies using metabolite measurements in molecular epidemiology and genetic studies. Although the environment influences metabolism, the identification of the genetic determinants of metabolic phenotypes (metabotypes) was made possible by the development of metabotype quantitative trait locus (mQTL) mapping and metabolomic genome-wide association studies (mGWAS) in a rigorous statistical genetics framework, deriving associations between metabolite concentrations and genetic polymorphisms. However, given the complexity of the biomolecular events involved in the regulation of metabolic patterns, alternative network biology approaches have also been recently introduced, such as integrated metabolome and interactome mapping (iMIM). This unprecedented convergence of metabolic biochemistry, quantitative genetics and network biology already has had a strong impact on the role of the metabolome in biomedical sciences, and this review gives a foretaste of its anticipated successes in eventually delivering personalized medicine. © 2012 The Royal Society of Chemistry. Source

Pollock K.M.,Imperial College London
The Journal of infectious diseases | Year: 2013

Changes in the phenotype and function of Mycobacterium tuberculosis (M. tuberculosis)-specific CD4+ and CD8+ T-cell subsets in response to stage of infection may allow discrimination between active tuberculosis and latent tuberculosis infection. A prospective comparison of M. tuberculosis-specific cellular immunity in subjects with active tuberculosis and latent tuberculosis infection, with and without human immunodeficiency virus (HIV) coinfection. Polychromatic flow cytometry was used to measure CD4+ and CD8+ T-cell subset phenotype and secretion of interferon γ (IFN-γ), interleukin 2 (IL-2), and tumor necrosis factor α (TNF-α). Frequencies of CD4+ and CD8+ cells secreting IFN-γ-only, TNF-α-only and dual IFN-γ/TNF-α were greater in active tuberculosis vs latent tuberculosis infection. All M. tuberculosis-specific CD4+ subsets, with the exception of IL-2-only cells, switched from central to effector memory phenotype in active tuberculosis vs latent tuberculosis infection, accompanied by a reduction in IL-7 receptor α (CD127) expression. The frequency of PPDspecific CD4+ TNF-α-only-secreting T cells with an effector phenotype accurately distinguished active tuberculosis from latent tuberculosis infection with an area under the curve of 0.99, substantially more discriminatory than measurement of function alone. Combined measurement of T-cell phenotype and function defines a highly discriminatory biomarker of tuberculosis disease activity. Unlocking the diagnostic and monitoring potential of this combined approach now requires validation in large-scale prospective studies. Source

Markides C.N.,Imperial College London
Applied Thermal Engineering | Year: 2012

This paper begins with an overview of the current supply and demand characteristics of primary energy for the provision of heat and power in the UK. This is followed by a brief review of a variety of solutions that are being proposed towards the establishment of a sustainable energy landscape, including clean coal, wind and solar energy. The discussion extends to the economics and performance of various renewable energy systems in comparison to fossil fuel equivalents. Placed in this context, the study then focuses specifically on the role of pumped heat, combined heat and power (CHP) schemes, and options for the recovery and conversion of waste heat into useful work, all of which have a potential to contribute towards the creation of a 'high-efficiency sustainable energy future'. It is concluded that although the problem is complex, the relative costs of competing technologies are not prohibitive, but comparable, leading to an inability to make a decisive choice and delaying progress. CHP and pumped heat are found to be similar in terms of overall efficiency, with the load factor (heat-to-power demand ratio) being of critical importance. Various waste heat conversion systems are also found to be similar in terms of the important indicator of power per unit cost. Crown Copyright © 2012. Source

Crowdy D.,Imperial College London
Physics of Fluids | Year: 2011

This paper shows that the frictional slip lengths for longitudinal Stokes shear flow over a superhydrophobic surface are precisely the blockage coefficients for uniform potential flow past screens with the same geometry. This observation facilitates useful knowledge transfer between two apparently disparate areas of fluid dynamics. Various ramifications of this realization are explored. © 2011 American Institute of Physics. Source

Uruchurtu L.I.,Imperial College London
Journal of High Energy Physics | Year: 2011

Four point functions of general N = 4 1/2-BPS primary fields, satisfying the next-next-to-extremality condition δ 1+δ 2+δ 3-δ 4 = 4 are studied at large N and strong coupling. We apply new techniques to evaluate the effective couplings in supergravity, and confirm that the four derivative couplings arising in the five-dimensional supergravity vanish on-shell. We then show that the four point amplitude resulting from supergravity naturally splits into a \free" and an interactive part which resembles an effective quartic interaction. The precise structure agrees with superconformal symmetry and supports the conjecture formulated by Dolan, Osborn and Nirschl regarding the strongly coupled form of four point correlators of chiral primary operators. We also evaluate the amplitude in large N free field SYM theory and discuss the results in the context of the correspondence. © 2011 SISSA. Source

Knoll R.,Imperial College London
Journal of Muscle Research and Cell Motility | Year: 2012

Myosin binding protein C (MYBPC) is a crucial component of the sarcomere and an important regulator of muscle function. While mutations in different myosin binding protein C (MYBPC) genes are well known causes of various human diseases, such as hypertrophic (HCM) and dilated (DCM) forms of cardiomyopathy as well as skeletal muscular disorders, the underlying molecular mechanisms remain not well understood. A variety of MYBPC3 (cardiac isoform) mutations have been studied in great detail and several corresponding genetically altered mouse models have been generated. Most MYBPC3 mutations may cause haploinsufficiency and with it they may cause a primary increase in calcium sensitivity which is potentially able to explain major features observed in HCM patients such as the hypercontractile phenotype and the well known secondary effects such as myofibrillar disarray, fibrosis, myocardial hypertrophy and remodelling including arrhythmogenesis. However the presence of poison peptides in some cases cannot be fully excluded and most probably other mechanisms are also at play. Here we shall discuss MYBPC interacting proteins and possible pathways linked to cardiomyopathy and heart failure. © 2011 The Author(s). Source

Edwards C.,Imperial College London
Journal of Clinical Endocrinology and Metabolism | Year: 2012

Context: Proinflammatory cytokines activate the hypothalamic pituitary adrenal axis in the acute phase but not with chronic inflammation; indeed, the hypothalamic pituitary adrenal axis is subtly subnormal, with apparently low ACTH and cortisol secretion. This paper reviews evidence that suggests that this is not simply an adaptation to chronic stress. These patients have increased conversion of inactive cortisone (E) to cortisol (F) by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Expression of this enzyme is markedly enhanced by TNF, an important autocrine protective mechanism at the inflammatory site. Evidence Acquisition and Synthesis: This report reviews the current understanding of the interaction between TNF and 11β-HSD1 in patients with chronic inflammatory disease. It is based on publications from PubMed and the Science Citation Index. Conclusions: The systemic effects of enhancing 11β-HSD1 activity may amplify the inflammatory response. Thus, increased conversion of cortisone to cortisol can alter the circadian rhythm of cortisol secretion (lower nadir, later rise, impaired stress response) with consequent relative nocturnal cortisol deficiency when inflammatory cytokines are highest. This could contribute to the circadian symptomatology in rheumatoid arthritis, the effectiveness of early morning (0200 h) low-dose corticosteroids, the significant correlation between total body 11β-HSD1 activity and erythrocyte sedimentation rate, and the effectiveness of 11 β-HSD inhibition in both the prevention and treatment of adjuvant arthritis in rat models of rheumatoid arthritis. It could also explain why anti-TNF therapy benefit can be predicted on the basis of the pretreatment plasma cortisol and the subsequent cortisol rise. In contrast, this mechanism is likely to be beneficial in the body's response to chronic infections such as tuberculosis and could explain why anti-TNF treatment markedly increases the risk of reactivation of the disease. Copyright © 2012 by The Endocrine Society. Source

Delves M.J.,Imperial College London
Future Medicinal Chemistry | Year: 2012

Malaria is a disease with a devastating impact affecting 216 million people each year and causing 655,000 deaths, most of which are children under 5 years old. Recent appreciation that malaria eradication will require novel interventions to target the parasite during transmission from the human host to the mosquito has lead to an exciting surge in activity to develop transmission-blocking drugs and the high-throughput assays to screen for them. This article presents an overview of transmission-stage cell biology and discusses its impact on assay development to provide a context for researchers to evaluate the relative merits/drawbacks of both screening data obtained from current assays and considerations for future assay design. The most recent knowledge of the transmission-blocking properties of current antimalarial classes is also summarized and, underdeveloped targets for transmission-stage drug discovery are highlighted. © 2012 Future Science Ltd. Source

Baxter J.,University of Sussex | Aragon L.,Imperial College London
Trends in Genetics | Year: 2012

The compaction of chromatin that occurs when cells enter mitosis is probably the most iconic process of dividing cells. Mitotic chromosomal compaction or 'condensation' is functionally linked to resolution of chromosomal intertwines, transcriptional shut-off and complete segregation of chromosomes. At present, understanding of the molecular events required to convert interphase chromatin into mitotic chromosomes is limited. Here, we review recent advances in the field, focusing on potential chromosomal compaction mechanisms and their importance to chromosome segregation. We propose a model of how metaphase chromosomes could be shaped based on the enzymatic activities of condensin and topoisomerase II in overwinding and relaxation of the DNA fiber during mitosis. We suggest that condensin overwinding is an important requirement for intertwine resolution by topoisomerase II and, together with the inhibition of transcription, contributes to cytological mitotic chromosome appearance or 'condensation'. © 2011 Elsevier Ltd. Source

Proton exchange membrane fuel cells (PEM FCs) offer a promising alternative to internal combustion engines in road transport. During the last decade PEM FC research, development and demonstration (RD&D) activities have been steadily increasing worldwide, and targets have been set to begin their commercialisation in road transport by 2015-2020. However, there still is considerable uncertainty on whether these targets will actually be met. The picture is complex and market and technology issues are closely interlinked; investment in RD&D projects is essential but not sufficient; the development of suitable early markets is also necessary and policy is set to play an important role. Auxiliary power units (APUs) are generally regarded as one important early market for FCs in transport. This paper analyses the possible future market for diesel PEM FC APUs onboard long-haul trucks and its implications for the development of PEM FCs in general. The analysis, part of the project HyTRAN (EC Contract no. 502577), is aided by the use of a dynamic simulation model of technology and markets developed by the author. Results suggest that an interesting window of opportunity for diesel PEM FC APUs exists but this is subject to additional research particularly targeted at the rapid development of fuel processors. © 2009 Elsevier Ltd. All rights reserved. Source

Crowdy D.,Imperial College London
Physics of Fluids | Year: 2011

The exact solutions due to Philip [ZAMP 23, 353 (1972)] for Stokes shear flow over a periodic array of no-shear slots embedded in a no-slip surface are generalized to account for an arbitrary pattern of no-shear slots in each period window. The slots, or grooves, in each period window run parallel to each other, and are of infinite length, but their widths and separations can be specified arbitrarily. Explicit solutions are found both for longitudinal and transverse flows over the composite grooved surface. Analytical expressions for the transverse and longitudinal slip lengths associated with the microstructured surfaces are then found as functions of the geometrical parameters characterizing the surface. The formulae are relevant to a wide class of flow geometries and are expected to provide a useful tool in the design, analysis, and optimization of the friction properties of grooved microstructured superhydrophobic surfaces. The results are used to show that introducing even a very small wetted region in a no-shear slot can have a significant influence on the effective slip length. © 2011 American Institute of Physics. Source

Bain B.J.,Imperial College London | Ahmad S.,Queen Mary, University of London
British Journal of Haematology | Year: 2014

Since the publication of the 2001 and 2008 World Health Organization classifications of tumours of haematopoietic and lymphoid tissues, there has been an increasing move towards classification of haematological neoplasms on the basis of the underlying molecular genetic disorder. In recent decades there have been a significant number of reports of haematological neoplasms with rearrangement of JAK2. Published data on such cases have therefore been analysed to determine if any specific entities could be identified. On the basis of this analysis, it is suggested that lymphoid and myeloid neoplasms associated with t(8;9)(p22;p24); PCM1-JAK2 fusion should be recognized as an entity. Furthermore, lymphoid and myeloid neoplasms associated respectively with t(9;12)(p24;p13); ETV6-JAK2 and with t(9;22)(p24;q11·2); BCR-JAK2 should be documented carefully in order to define their features more clearly and assess whether they can be recognized as entities. Identification of all these conditions is important because of the possibility of response to JAK2 inhibitors. © 2014 John Wiley & Sons Ltd. Source

Elkington P.T.,University of Southampton | Friedland J.S.,Imperial College London
The Lancet Infectious Diseases | Year: 2015

Tuberculosis remains a global health pandemic. The current depiction of the Mycobacterium tuberculosis life cycle proposes that airborne bacilli are inhaled and phagocytosed by alveolar macrophages, resulting in the formation of a granuloma that ruptures into the airways to reinitiate the infectious cycle. However, this widely proposed model overlooks the fact, established 100 years ago, that the initial site of M tuberculosis implantation is in the lower zones of the lungs, whereas infectious cavitary pulmonary disease develops at the lung apices. The immunological events at these two pulmonary locations are different-cavitation only occurs in the apices and not in the bases. Yet the current conceptual model of tuberculosis renders the immunology of these two temporally and spatially separated events identical. One key consequence is that prevention of primary childhood tuberculosis at the lung bases is regarded as adequate immunological protection, but extensive evidence shows that greater immunity could predispose to immunopathology and transmission at the lung apex. A much greater understanding of time and place in the immunopathological mechanisms underlying human tuberculosis is needed before further pre-exposure vaccination trials can be done. © 2015 Elsevier Ltd. Source

Vanner M.R.,University of Vienna | Aspelmeyer M.,University of Vienna | Kim M.S.,Imperial College London
Physical Review Letters | Year: 2013

We introduce a method that can orthogonalize any pure continuous variable quantum state, i.e., generate a state |ψ ⊥⟩ from |ψ⟠© where âŸ̈ψ|ψ⊥⠟©=0, which does not require significant a priori knowledge of the input state. We illustrate how to achieve orthogonalization using the Jaynes-Cummings or beamsplitter interaction, which permits realization in a number of physical systems. Furthermore, we demonstrate how to orthogonalize the motional state of a mechanical oscillator in a cavity optomechanics context by developing a set of coherent phonon level operations. As the mechanical oscillator is a stationary system, such operations can be performed at multiple times providing considerable versatility for quantum state engineering applications. Utilizing this, we additionally introduce a method how to transform any known pure state into any desired target state. Published by the American Physical Society under the terms of the uri xlink:href="http:// creativecommons.org/licenses/by/3.0/"Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Source

Vassilicos J.C.,Imperial College London
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2011

The von Kárman-Howarth equation implies an infinity of invariants corresponding to an infinity of different asymptotic behaviours of the double and triple velocity correlation functions at infinite separations. Given an asymptotic behaviour at infinity for which the Birkhoff-Saffman invariant is not infinite, there are either none, or only one or only two finite invariants. If there are two, one of them is the Loitsyansky invariant and the decay of large eddies cannot be self-similar. We examine the consequences of this infinity of invariants on a particular family of exact solutions of the von Kárman-Howarth equation. © 2011 Elsevier B.V. Source

Inositol phospholipids have emerged as important key players in a wide variety of cellular functions. Among the seven existing inositol phospholipids, phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P(2)) has attracted much attention in recent years due to its important role in numerous cellular signaling events and regulations, which in turn impact several human diseases. This particular lipid is recognized in the cell by specific lipid binding domains, such as the Pleckstrin-homology (PH) domain, which is also employed as a tool to monitor this important lipid. Here, we describe the synthesis and biological characterization of a small molecule that mimics the PH domain as judged by its ability to bind specifically to only PI(4,5)P(2) and effectively compete with the PH domain in vitro and in a cellular environment. The binding constant of this small molecule PH domain mimetic (PHDM) was determined to be 17.6 ± 10.1 μM, similar in potency to the PH domain. Using NIH 3T3 mouse fibroblast cells we demonstrated that this compound is cell-permeable and able to modulate PI(4,5)P(2)-dependent effects in a cellular environment such as the endocytosis of the transferrin receptor, loss of mitochondria, as well as stress fiber formation. This highly PI(4,5)P(2)-specific chemical mimetic of a PH domain not only is a powerful research tool but might also be a lead compound in future drug developments targeting PI(4,5)P(2)-dependent diseases such as Lowe syndrome. Source

Albrecht T.,Imperial College London
ACS Nano | Year: 2011

Nanopore-based single-molecule sensors have become an important class of analytical devices that have in some cases already reached the market place. Traditionally operated in a two-electrode configuration, devices with three or more electrodes have emerged recently, for example with a view on switching the transport properties of the nanopore or even tunneling-based detection of analytes with the ultimate goal of inexpensive and ultrafast DNA sequencing. How do these additional electrodes affect the current distribution in the cell and hence the sensor performance? This is significantly less clear and thus in focus here. We use impedance modeling of a prototypical three-electrode nanopore sensor and show that, depending on the conditions, standard experimental device characterization is severely affected by the presence of the third electrode. On the other hand, the simulations also provide guidelines on how to avoid such complications, identify "safe" operating conditions, and design criteria for optimized nanopore sensors. © 2011 American Chemical Society. Source

Tseytlin A.A.,Imperial College London
Nuclear Physics B | Year: 2013

We study 4-dimensional higher-derivative conformal higher-spin (CHS) fields generalizing Weyl graviton and conformal gravitino. They appear, in particular, as "induced" theories in the AdS/CFT context. We consider their partition function on curved Einstein-space backgrounds like (A)dS or sphere and Ricci-flat spaces. Remarkably, the bosonic (integer spin s) CHS partition function appears to be given by a product of partition functions of the standard 2nd-derivative "partially massless" spin s fields, generalizing the previously known expression for the 1-loop Weyl graviton (s=2) partition function. We compute the corresponding spin s Weyl anomaly coefficients as and cs. Our result for as reproduces the expression found recently in arXiv:1306.5242 by an indirect method implied by AdS/CFT (which relates the partition function of a CHS field on S4 to a ratio of known partition functions of massless higher-spin field in AdS5 with alternate boundary conditions). We also obtain similar results for the fermionic CHS fields. In the half-integer s case the CHS partition function on (A)dS background is given by the product of squares of "partially massless" spin s partition functions and one extra factor corresponding to a special massive conformally invariant spin s field. It was noticed in arXiv:1306.5242 that the sum of the bosonic as coefficients over all s is zero when computed using the ζ-function regularization, and we observe that the same property is true also in the fermionic case. © 2013 Elsevier B.V. Source

Pusey M.F.,Imperial College London
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

The violation of a Bell inequality certifies the presence of entanglement even if neither party trusts their measurement devices. Recently Moroder showed how to make this statement quantitative, using semidefinite programming to calculate how much entanglement is certified by a given violation. Here I adapt their techniques to the case in which Bob's measurement devices are in fact trusted, the setting for Einstein-Podolsky-Rosen steering inequalities. Interestingly, all of the steering inequalities studied turn out to require negativity for their violations. This supports a significant strengthening of Peres's conjecture that negativity is required to violate a bipartite Bell inequality. © 2013 American Physical Society. Source

Barnes P.J.,Imperial College London
Pharmacological Reviews | Year: 2016

Multiple kinases play a critical role in orchestrating the chronic inflammation and structural changes in the respiratory tract of patients with asthma and chronic obstructive pulmonary disease (COPD). Kinases activate signaling pathways that lead to contraction of airway smooth muscle and release of inflammatory mediators (such as cytokines, chemokines, growth factors) as well as cell migration, activation, and proliferation. For this reason there has been great interest in the development of kinase inhibitors as anti-inflammatory therapies, particular where corticosteroids are less effective, as in severe asthma and COPD. However, it has proven difficult to develop selective kinase inhibitors that are both effective and safe after oral administration and this has led to a search for inhaled kinase inhibitors, which would reduce systemic exposure. Although many kinases have been implicated in inflammation and remodeling of airway disease, very few classes of drug have reached the stage of clinical studies in these diseases. The most promisingdrugs arep38MAPkinases, isoenzyme-selective PI3-kinases, Janus-activated kinases, and Syk-kinases, and inhaled formulations of these drugs are now in development. There has also been interest in developing inhibitors that block more than one kinase, because these drugs may be more effective and with less risk of losing efficacy with time. No kinase inhibitors are yet on the market for the treatment of airway diseases, but as kinase inhibitors are improved from other therapeutic areas there is hope that these drugs may eventually prove useful in treating refractory asthma and COPD. © 2016 by The American Society for Pharmacology and Experimental Therapeutics. Source

Santer M.,Imperial College London
International Journal of Solids and Structures | Year: 2010

The effect of material viscoelasticity on the stability of structures is investigated. It is demonstrated that viscoelastic effects can cause structures to exhibit temporary bistability in a deformed configuration. When this bistability is lost, the structure may suddenly jump back to its initial configuration in a phenomenon described as self-actuated snap back. It is shown for both a single degree of freedom system and a hemispherical cap that the viscoelastic behaviour may be inferred by consideration of the purely elastic response. These inferences are confirmed by means of finite element analysis. © 2010 Elsevier Ltd. All rights reserved. Source

Chung K.F.,Imperial College London
Pulmonary Pharmacology and Therapeutics | Year: 2011

Chronic cough remains a challenge to many clinicians because there is often no diagnostic link to causation, and because indirect antitussives are largely ineffective. Chronic cough can also be a predominant symptom associated with many chronic respiratory diseases such as COPD, asthma and pulmonary fibrosis. Chronic cough itself does impair the quality of life and is associated with psychological impairment. The symptoms associated with chronic cough include persistent tickling or irritating sensation in the chest or throat, hoarse voice, dysphonia or vocal cord dysfunction. Currently, the clinical diagnosis of cough is associated with chronic cough caused by airway eosinophilic conditions such as asthma, gastrooesophageal reflux disease or post-nasal drip (or upper airway syndrome), which implies cause and effect, or with chronic cough associated with other diseases such as COPD, cancer or heart failure, that does not necessarily imply cause and effect. A recently-recognised category is idiopathic cough, with no associated or causative diagnosis. We suggest that there is a better label needed for chronic cough, that includes the common association with a hypersensitive cough response to tussive stimuli such as capsaicin or citric acid. This would invoke a hypersensitive syndrome, and there are good reasons to use a new label that would encompass the problem of chronic cough: the chronic 'cough hypersensitivity syndrome'. This would focus the problem on the cough symptomatology and lead to greater focus on understanding the mechanisms of cough sensitisation, with the ultimate aim of obtaining more effective antitussives. © 2011 Elsevier Ltd. Source

Nikas G.K.,Imperial College London
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology | Year: 2010

Hydraulic seals are complicated machine elements. The engineering research on hydraulic reciprocating seals, which commenced roughly in the 1930s, has achieved a basic understanding of performance issues. This article provides a review of the experimental and theoretical research conducted over a period of eight decades, discussing more than 200 of the most significant publications from the related literature. The topics discussed include reciprocating seal designs, materials, experimental methods, theoretical studies, elastohydrodynamic lubrication, solid and contact mechanics, performance issues, and optimization. Source

Postma D.S.,University of Groningen | Bush A.,Imperial College London | Van Den Berge M.,University of Groningen
The Lancet | Year: 2015

Summary Chronic obstructive pulmonary disease is mainly a smoking-related disorder and affects millions of people worldwide, with a large effect on individual patients and society as a whole. Although the disease becomes clinically apparent around the age of 40-50 years, its origins can begin very early in life. Different risk factors in very early life - ie, in utero and during early childhood - drive the development of clinically apparent chronic obstructive pulmonary disease in later life. In discussions of which risk factors drive chronic obstructive pulmonary disease, it is important to realise that the disease is very heterogeneous and at present is largely diagnosed by lung function only. In this Review, we will discuss the evidence for risk factors for the various phenotypes of chronic obstructive pulmonary disease during different stages of life. © 2015 Elsevier Ltd. Source

Huhtaniemi I.,Imperial College London | Huhtaniemi I.,University of Turku
Asian Journal of Andrology | Year: 2014

Although suppressed serum testosterone (T) is common in ageing men, only a small proportion of them develop the genuine syndrome of low T associated with diffuse sexual (e.g., erectile dysfunction), physical (e.g. loss of vigor and frailty) and psychological (e.g., depression) symptoms. This syndrome carries many names, including male menopause or climacterium, andropause and partial androgen deficiency of the ageing male (PADAM). Late-onset hypogonadism (LOH) describes it best and is therefore generally preferred. The decrease of T in LOH is often marginal, and hypogonadism can be either due to primary testicular failure (low T, high luteinizing hormone (LH)) or secondary to a hypothalamic-pituitary failure (low T, low or inappropriately normal LH). The latter form is more common and it is usually associated with overweight/obesity or chronic diseases (e.g., type 2 diabetes mellitus, the metabolic syndrome, cardiovascular and chronic obstructive pulmonary disease, and frailty). A problem with the diagnosis of LOH is that often the symptoms (in 20%-40% of unselected men) and low circulating T (in 20% of men >70 years of age) do not coincide in the same individual. The European Male Ageing Study (EMAS) has recently defined the strict diagnostic criteria for LOH to include the simultaneous presence of reproducibly low serum T (total T <11 nmol l -1 and free T <220 pmol l-1 ) and three sexual symptoms (erectile dysfunction, and reduced frequency of sexual thoughts and morning erections). By these criteria, only 2% of 40- to 80-year-old men have LOH. In particular obesity, but also impaired general health, are more common causes of low T than chronological age per se. Evidence-based information whether, and how, LOH should be treated is sparse. The most logical approach is lifestyle modification, weight reduction and good treatment of comorbid diseases. T replacement is widely used for the treatment, but evidence-based information about its real benefits and short- and long-term risks, is not yet available. In this review, we will summarize the current concepts and controversies in the pathogenesis, diagnosis and treatment of LOH. © 2014 AJA, SIMM & SJTU. All rights reserved. Source

Xun W.W.,Imperial College London
International journal of public health | Year: 2010

Climate change is now thought to be unequivocal, while its potential effects on global and public health cannot be ignored. However, the complexities of the causal webs, the dynamics of the interactions and unpredictability mean that climate change presents new challenges to epidemiology and magnifies existing methodological problems. This article reviews a number of such challenges, including topics such as exposure assessment, bias, confounding, causal complexities and uncertainties, with examples and recommendations provided where appropriate. Hence, epidemiology must continue to adapt by developing new approaches and the integration of other disciplines such as geography and climatology, with an emphasis on informing policy-making and disseminating knowledge beyond the field. Source

Forbes S.J.,University of Edinburgh | Rosenthal N.,Imperial College London | Rosenthal N.,Monash University
Nature Medicine | Year: 2014

Chronic diseases confer tissue and organ damage that reduce quality of life and are largely refractory to therapy. Although stem cells hold promise for treating degenerative diseases by 'seeding' injured tissues, the regenerative capacity of stem cells is influenced by regulatory networks orchestrated by local immune responses to tissue damage, with macrophages being a central component of the injury response and coordinator of tissue repair. Recent research has turned to how cellular and signaling components of the local stromal microenvironment (the 'soil' to the stem cells' seed), such as local inflammatory reactions, contribute to successful tissue regeneration. This Review discusses the basic principles of tissue regeneration and the central role locally acting components may play in the process. Application of seed-and-soil concepts to regenerative medicine strengthens prospects for developing cell-based therapies or for promotion of endogenous repair. © 2014 Nature America, Inc. Source

Diez-Gonzalez S.,Imperial College London
Current Organic Chemistry | Year: 2011

The last decade has witnessed a tremendous increase of the studies concerning [3+2] cycloaddition reactions of azides and alkynes. The recent discovery of copper(I) species as efficient catalysts for this transformation is at the origin of this true explosion. In contrast with classical thermal reactions, copper catalysis leads to the regioselective formation of 1,4-disubstituted 1,2,3-triazoles in high yields and under simple reaction conditions. This transformation has indeed become the most prominent example of the principles of Click chemistry, postulated in 2001 by Sharpless and co-workers. Despite the ever-increasing interest in this process, the use of ligands in this context remains minor when compared to ligandless systems. Nevertheless, besides overcoming the inherent limitations of ligandless systems, the use of ligands in this context has been shown to increase and, more importantly, modulate the catalytic activity of the metal center. Herein, the catalytic activities of ligated copper systems are reviewed in a way intended inspirational for future developments in this field. © 2011 Bentham Science Publishers Ltd. Source

Cargill P.J.,Imperial College London | Cargill P.J.,University of St. Andrews
Astrophysical Journal | Year: 2014

The temperature dependence of the emission measure (EM) in the core of active regions coronal loops is an important diagnostic of heating processes. Observations indicate that EM(T) ∼ Ta below approximately 4 MK, with 2 < a < 5. Zero-dimensional hydrodynamic simulations of nanoflare trains are used to demonstrate the dependence of a on the time between individual nanoflares (TN) and the distribution of nanoflare energies. If TN is greater than a few thousand seconds, a < 3. For smaller values, trains of equally spaced nanoflares cannot account for the observed range of a if the distribution of nanoflare energies is either constant, randomly distributed, or a power law. Power law distributions where there is a delay between consecutive nanoflares proportional to the energy of the second nanoflare do lead to the observed range of a. However, TN must then be of the order of hundreds to no more than a few thousand seconds. If a nanoflare leads to the relaxation of a stressed coronal field to a near-potential state, the time taken to build up the required magnetic energy is thus too long to account for the EM measurements. Instead, it is suggested that a nanoflare involves the relaxation from one stressed coronal state to another, dissipating only a small fraction of the available magnetic energy. A consequence is that nanoflare energies may be smaller than previously envisioned. © 2014. The American Astronomical Society. All rights reserved. Source

Marcano Belisario J.S.,Imperial College London
The Cochrane database of systematic reviews | Year: 2013

Asthma is one of the most common long-term conditions worldwide, which places considerable pressure on patients, communities and health systems. The major international clinical guidelines now recommend the inclusion of self management programmes in the routine management of did not conduct a meta-analysis of the data extracted due to the considerable degree of heterogeneity between these studies. Instead we adopted a narrative synthesis approach. Overall, the results were inconclusive and we judged the evidence to have a GRADE rating of low quality because further evidence is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. In addition, there was not enough information in one of the included studies to assess the risk of bias for the majority of the domains. Although the other included study was methodologically rigorous, it was not possible to blind participants or personnel in the study. Moreover, there are concerns in both studies in relation to attrition bias and other sources of bias.One study showed that the use of a smartphone app for the delivery of an asthma self management programme had no statistically significant effect on asthma symptom scores (mean difference (MD) 0.01, 95% confidence interval (CI) -0.23 to 0.25), asthma-related quality of life (MD of mean scores 0.02, 95% CI -0.35 to 0.39), unscheduled visits to the emergency department (OR 7.20, 95% CI 0.37 to 140.76) or frequency of hospital admissions (odds ratio (OR) 3.07, 95% CI 0.32 to 29.83). The other included study found that the use of a smartphone app resulted in higher asthma-related quality of life scores at six-month follow-up (MD 5.50, 95% CI 1.48 to 9.52 for the physical component score of the SF-12 questionnaire; MD 6.00, 95% CI 2.51 to 9.49 for the mental component score of the SF-12 questionnaire), improved lung function (PEFR) at four (MD 27.80, 95% CI 4.51 to 51.09), five (MD 31.40, 95% CI 8.51 to 54.29) and six months (MD 39.20, 95% CI 16.58 to 61.82), and reduced visits to the emergency department due to asthma-related complications (OR 0.20, 95% CI 0.04 to 0.99). Both studies failed to find any statistical differences in terms of adherence to the intervention and occurrence of other asthma-related complications. The current evidence base is not sufficient to advise clinical practitioners, policy-makers and the general public with regards to the use of smartphone and tablet computer apps for the delivery of asthma self management programmes. In order to understand the efficacy of apps as standalone interventions, future research should attempt to minimise the differential clinical management of patients between control and intervention groups. Those studies evaluating apps as part of complex, multicomponent interventions, should attempt to tease out the relative contribution of each intervention component. Consideration of the theoretical constructs used to inform the development of the intervention would help to achieve this goal. Finally, researchers should also take into account: the role of ancillary components in moderating the observed effects, the seasonal nature of asthma and long-term adherence to self management practices. Source

Boasso A.,Imperial College London
Current Medicinal Chemistry | Year: 2011

Indoleamine 2,3-dioxygenase (IDO) is an immunoregulatory enzyme which plays a key role in maintaining the physiologic immune balance between the efficient responses to insulting pathogens and the control of harmful autoimmune reactions. During HIV infection, multiple mechanisms involving both viral and cellular components, contribute to enhance IDO expression and activity in an uncontrolled manner. The downstream effects of IDO overactivation collectively contribute to the immune alterations which characterize HIV disease. This review explores the cellular and molecular pathways which result in IDO upregulation during HIV infection and considers the consequences of IDO hyperactivity on the immune system, their relevance in the context of HIV immunopathogenesis and the potential for specific therapeutic intervention. © 2011 Bentham Science Publishers Ltd. Source

Markus M.B.,Imperial College London
Parasitology Research | Year: 2011

In 1978, the nature of the hypnozoite was discussed in an article that appeared in a relatively obscure journal, which is also where the term was adopted for Plasmodium (a little-known fact). As a result, that commentary on the use of the word "hypnozoite" has been almost completely overlooked. Although the publication is now more than three decades old, the analysis remains valid today. It is explained in the present paper that like "merozoite" and "sporozoite", the name " hypnozoite" is applicable not only to a latent stage in the life cycle of Plasmodium but to some apparently dormant forms of other kinds of apicomplexan parasites as well. Merozoites of different genera of parasitic protozoa are not necessarily the same biologically and/or otherwise. Similarly, although the hypnozoite concept relates primarily to pre-merozoite stages, some atypical post-divisional apicomplexan forms might also be hypnozoites. Examples are likewise given of latent organisms that, in contrast, are clearly not hypnozoites, such as dormant merozoites in malaria infections. Lastly, the plasmodial hypnozoite is placed in context in relation to the relatively unfamiliar (nomenclaturally) malarial bradysporozoite, chronozoite, dormozoite, merophore, merosome and x body. This paper is based on a presentation by the author, as a Life Member of the American Society of Tropical Medicine and Hygiene, to its 59th Annual Meeting in Atlanta, Georgia, USA, 3-7 November 2010. © 2010 Springer-Verlag. Source

Sugand K.,Imperial College London
Anatomical sciences education | Year: 2010

Anatomy has historically been a cornerstone in medical education regardless of nation or specialty. Until recently, dissection and didactic lectures were its sole pedagogy. Teaching methodology has been revolutionized with more reliance on models, imaging, simulation, and the Internet to further consolidate and enhance the learning experience. Moreover, modern medical curricula are giving less importance to anatomy education and to the acknowledged value of dissection. Universities have even abandoned dissection completely in favor of user-friendly multimedia, alternative teaching approaches, and newly defined priorities in clinical practice. Anatomy curriculum is undergoing international reformation but the current framework lacks uniformity among institutions. Optimal learning content can be categorized into the following modalities: (1) dissection/prosection, (2) interactive multimedia, (3) procedural anatomy, (4) surface and clinical anatomy, and (5) imaging. The importance of multimodal teaching, with examples suggested in this article, has been widely recognized and assessed. Nevertheless, there are still ongoing limitations in anatomy teaching. Substantial problems consist of diminished allotted dissection time and the number of qualified anatomy instructors, which will eventually deteriorate the quality of education. Alternative resources and strategies are discussed in an attempt to tackle these genuine concerns. The challenges are to reinstate more effective teaching and learning tools while maintaining the beneficial values of orthodox dissection. The UK has a reputable medical education but its quality could be improved by observing international frameworks. The heavy penalty of not concentrating on sufficient anatomy education will inevitably lead to incompetent anatomists and healthcare professionals, leaving patients to face dire repercussions. Copyright 2010 American Association of Anatomists. Source

Barraclough T.G.,Imperial College London
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010

Current approaches to studying the evolution of biodiversity differ in their treatment of species and higher level diversity patterns. Species are regarded as the fundamental evolutionarily significant units of biodiversity, both in theory and in practice, and extensive theory explains how they originate and evolve. However, most species are still delimited using qualitative methods that only relate indirectly to the underlying theory. In contrast, higher level patterns of diversity have been subjected to rigorous quantitative study (using phylogenetics), but theory that adequately explains the observed patterns has been lacking. Most evolutionary analyses of higher level diversity patterns have considered non-equilibrium explanations based on rates of diversification (i.e. exponentially growing clades), rather than equilibrium explanations normally used at the species level and below (i.e. constant population sizes). This paper argues that species level and higher level patterns of diversity can be considered within a common framework, based on equilibrium explanations. It shows how forces normally considered in the context of speciation, namely divergent selection and geographical isolation, can generate evolutionarily significant units of diversity above the level of reproductively isolated species. Prospects for the framework to answer some unresolved questions about higher level diversity patterns are discussed. ©2010 The Royal Society. Source

Faye I.,University of Stockholm | Lindberg B.G.,Imperial College London
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2016

Four decades ago, immunological research was dominated by the field of lymphoid biology. It was commonly accepted that multicellular eukaryotes defend themselves through phagocytosis. The lack of lymphoid cells in insects and other simpler animals, however, led to the common notion that they might simply lack the capacity defend themselves with humoral factors. This view was challenged by microbiologist Hans G. Boman and co-workers in a series of publications that led to the advent of antimicrobial peptides as a universal arm of the immune system. Besides ingenious research, Boman ignited his work by posing the right questions. He started off by asking himself a simple question: ‘Antibodies take weeks to produce while many microbes divide hourly; so how come we stay healthy?’. This led to two key findings in the field: the discovery of an inducible and highly potent antimicrobial immune response in Drosophila in 1972, followed by the characterization of cecropin in 1981. Despite broadly being considered an insect-specific response at first, the work of Boman and co-workers eventually created a bandwagon effect that unravelled various aspects of innate immunity. This article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’. © 2016 The Author(s) Published by the Royal Society. All rights reserved. Source

Chevin L.-M.,Imperial College London
Biology Letters | Year: 2011

Distributions of mutation fitness effects from evolution experiments are available in an increasing number of species, opening the way for a vast array of applications in evolutionary biology. However, comparison of estimated distributions among studies is hampered by inconsistencies in the definitions of fitness effects and selection coefficients. In particular, the use of ratios of Malthusian growth rates as 'relative fitnesses' leads to wrong inference of the strength of selection. Scaling Malthusian fitness by the generation time may help overcome this shortcoming, and allow accurate comparison of selection coefficients across species. For species reproducing by binary fission (neglecting cellular death), In2 can be used as a correction factor, but in general, the growth rate and generation time of the wild-type should be provided in studies reporting distribution of mutation fitness effects. I also discuss how density and frequency dependence of population growth affect selection and its measurement in evolution experiments. © 2011 The Royal Society. Source

Gilestro G.F.,Imperial College London
Nature protocols | Year: 2012

In the past decade, Drosophila has emerged as an ideal model organism for studying the genetic components of sleep as well as its regulation and functions. In fruit flies, sleep can be conveniently estimated by measuring the locomotor activity of the flies using techniques and instruments adapted from the field of circadian behavior. However, proper analysis of sleep requires degrees of spatial and temporal resolution higher than is needed by circadian scientists, as well as different algorithms and software for data analysis. Here I describe how to perform sleep experiments in flies using techniques and software (pySolo and pySolo-Video) previously developed in my laboratory. I focus on computer-assisted video tracking to monitor fly activity. I explain how to plan a sleep analysis experiment that covers the basic aspects of sleep, how to prepare the necessary equipment and how to analyze the data. By using this protocol, a typical sleep analysis experiment can be completed in 5-7 d. Source

Ashton-Rickardt P.G.,Imperial College London
Immunological Reviews | Year: 2010

Serine proteases control a wide variety of physiological and pathological processes in multi-cellular organisms, including blood clotting, cancer, cell death, osmoregulation, tissue remodeling, and immunity to infection. Cytotoxic T lymphocytes (CTLs) are required for adaptive cell-mediated immunity to intracellular pathogens by killing infected cells and through the development of memory T cells. Serine proteases not only allow a CTL to kill but also impose homeostatic control on CTL number. Serine protease inhibitors (serpins) are the physiological regulators of serine proteases' activity. In this review, I discuss the role of serpins in controlling the recognition of antigen, effector function, and homeostatic control of CTLs through the inhibition of physiological serine protease targets. An emerging view of serpins is that they are important promoters of cellular viability through their inhibition of executioner proteases. This view is discussed in the context of the T-lymphocyte survival during effector responses and the development and persistence of long-lived memory T cells. Given the important role serpins play in CTL immunity, I discuss the potential for developing new immunotherapeutic approaches based directly on serpins or knowledge gained from identifying their physiologically relevant protease targets. © 2010 John Wiley & Sons A/S. Source

Gavins F.N.E.,Imperial College London
Trends in Pharmacological Sciences | Year: 2010

Ischaemia-reperfusion (I/R) injury is a common feature of several diseases associated with high morbidity and mortality, such as stroke and myocardial infarction. The damaged tissue displays cardinal signs of inflammation and microvascular injury that, unless resolved, lead to long-term tissue damage with associated dysfunction. Current therapies are limited and are often associated with many side effects. Increasing evidence suggests that members of the formyl peptide receptor (FPR) family, in particular human FPR2/ALX, might have an important role in the pathophysiology of I/R injury. It was recently demonstrated that several peptides and non-peptidyl small-molecule compounds have anti-inflammatory and pro-resolving properties via their action on members of the FPR family. Here I review this evidence and suggest that FPR ligands, particularly in the brain, could be novel and exciting anti-inflammatory therapeutics for the treatment of a variety of clinical conditions, including stroke. © 2010 Elsevier Ltd. Source

Wang Y.,Imperial College London
Geophysical Journal International | Year: 2013

This paper presents a novel system for computing seismic slowness paths and the traveltime field simultaneously in anisotropic media, in which the ray path concept is replaced with the concept of slowness paths. Like ray paths in isotropic media, slowness paths are orthogonal to the wave fronts in anisotropic media. The novelty of the proposed system relies on the explicit normal constraint that slowness vectors are perpendicular to wave fronts. While the system finds the positions of sequential wave fronts with a constant time interval, samples of consecutive wave fronts represent slowness paths which are normal to wave fronts and follow phase velocities in anisotropic media. The simultaneous calculation can remove any shadow zones where paths might fail to emerge by path-tracing and meanwhile avoid the instability problem in conventional eikonal-equation solution for traveltimes. While any differential discontinuity (such as cusps in a wave front) causes numerical instability, it is dealt with by a least-squares smoothing strategy along the wave front. The feasibility is demonstrated using numerical examples from simple to realistic anisotropic models. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society. Source

Sydoruk O.,Imperial College London
Journal of Physics D: Applied Physics | Year: 2013

Understanding the properties of plasmons in two-dimensional channels is important for developing methods of terahertz generation. This paper presents a modal analysis of plasmonic reflection in open channels supporting dc currents. As it shows, the plasmons can be amplified upon reflection if a dc current flows away from a conducting boundary; de-amplification occurs for the opposite current direction. The problem is solved analytically, based on a perturbation calculation, and numerically, and agreement between the methods is demonstrated. The power radiated by a channel is found to be negligible, and plasmon reflection in open channels is shown to be similar to that in closed channels. Based on this similarity, the oscillator designs developed earlier for closed channels could be applicable also for open ones. The results develop the modal-decomposition technique further as an instrument for the design of terahertz plasmonic sources. © 2013 IOP Publishing Ltd. Source

Masato G.,University of Reading | Hoskins B.J.,Imperial College London | Woollings T.,University of Reading
Journal of Climate | Year: 2013

The frequencies of atmospheric blocking in both winter and summer and the changes in them from the twentieth to the twenty-first centuries as simulated in 12 models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are analyzed. The representative concentration pathway 8.5 (RCP8.5) high emission scenario runs are used to represent the twenty-first century. The analysis is based on the wavebreaking methodology of Pelly and Hoskins. It differs from the Tibaldi and Molteni index in viewing equatorward cutofflows and poleward blocking highs in equal manner as indicating a disruption to the westerlies. One-dimensional and two-dimensional diagnostics are applied to identify blocking of the midlatitude storm track and also at higher latitudes. Winter blocking frequency is found to be generally underestimated. The models give a decrease in the European blocking maximum in the twenty-first century, consistent with the results in other studies. There is a mean twenty-first-century winter poleward shift of high-latitude blocking but little agreement between the models on the details. In summer, Eurasian blocking is also underestimated in the models, whereas it is now too large over the high-latitude ocean basins. A decrease in European blocking frequency in the twenty-first-century model runs is again found. However, in summer there is a clear eastward shift of blocking over eastern Europe and western Russia, in a region close to the blocking that dominated the Russian summer of 2010. While summer blocking decreases in general, the poleward shift of the storm track into the region of frequent high-latitude blocking may mean that the incidence of storms being obstructed by blocks may actually increase. © 2013 American Meteorological Society. Source

OBJECTIVES: B cells are central to the pathology of ANCA-associated vasculitis (AAV), a disease characterized by autoantibodies and effectively treated by rituximab. In addition to promoting inflammation, a subset of B cells act to suppress harmful autoimmune responses (Breg). The balance of effector and regulatory B cell subsets in AAV is not known. This study was conducted to assess the relative frequency of these subsets during different states of disease activity.METHODS: B memory (Bmem), naive (Bnaive) and regulatory (Breg) subsets were defined by their relative expression of CD24 and CD38. Function was assessed by cytokine production and suppressive action on CD4(+) Th1 activation evaluated in a co-culture system.RESULTS: Compared with healthy controls, the frequency of Breg (CD24(hi)CD38(hi)) was significantly reduced during disease remission in both proteinase 3 (PR3)- and MPO-ANCA patients and during acute disease in PR3-ANCA patients, while the frequency of memory cells (CD24(hi)CD38(lo)) was reduced during active disease and restored during remission. Breg cell frequency showed a positive correlation, while Bmem had an inverse correlation with IL-10 production in vitro. B and T cell co-cultures revealed that memory and naive B cell subsets augmented Th1 activation in vitro, which was prevented by Breg, and this pattern did not differ between remission AAV patients and controls.CONCLUSION: In remission there is a numerical, but not functional, deficiency in Breg and preservation of Bmem associated with reduced IL-10 production and increased Th1 activation in vitro. This imbalance may contribute to the high rate of relapse observed in AAV, especially in PR3-ANCA patients. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com. Source

Arulkumaran N.,Imperial College London
Rheumatology (Oxford, England) | Year: 2011

ANCA-associated vasculitis and interstitial lung disease (ILD) are uncommon conditions. The occurrence of both diseases in the same patient is increasingly recognized. Our aim was to ascertain the characteristics and outcomes of patients with ILD and ANCA-associated vasculitis. A retrospective observational cohort study was performed. Patients who presented to the Hammersmith Hospital, London, with ANCA-associated vasculitis [granulomatosis with polyangiitis (Wegener's), microscopic polyangiitis (MPA) or Churg-Strauss syndrome] who also had ILD were included. Following hospital discharge, all patients were followed up in a multi-disciplinary vasculitis clinic. We recorded patient demographics, diagnostic tests, treatment, complications and mortality. ILD was observed in 2.7% (n = 14) of our patients with ANCA-associated vasculitis (n = 510); all had MPO-ANCA and a clinical diagnosis of MPA, giving a prevalence of 7.2% in patients with MPA (n = 194). There was no significant difference in survival between patients with MPA and ILD and those with MPA alone. It is important that physicians are aware of this clinical association and the presence of ILD should be considered in all patients with ANCA-associated vasculitis, especially those with MPO-ANCA. The possibility that patients with ILD may subsequently develop features of systemic vasculitis should also be remembered. Source

Bagwan I.N.,Imperial College London
Virchows Archiv : an international journal of pathology | Year: 2011

Cardiac sarcoidosis has been known to give rise to heart failure, arrhythmias and sudden cardiac death. We have a large database of sudden cardiac death cases at the CRY Centre for Cardiac Pathology at Imperial College, London, UK in which we found 17 of 1,720 cases with a diagnosis of cardiac sarcoid. Macroscopic examination showed a variety of findings including left ventricular hypertrophy, a dilated thin-walled left ventricle, areas of fibrosis, changes resembling arrhythmogenic right ventricular cardiomyopathy and in some cases, no gross abnormalities. Histological examination revealed large areas of fibrosis and focal lymphocytic inflammation mimicking infarction/myocarditis. Careful search had to be made for non-necrotizing granulomata, since the lymphocytic foci, fibrosis and granulation tissue often predominated throughout the heart. The conduction tissue is often not sampled at autopsy despite the history of heart block. The heterogeneous nature of the macroscopic appearance and histological findings means that widespread sampling of the heart and the conduction system is essential in cases of sudden death in order that a diagnosis of myocardial sarcoidosis is not missed. Source

Rezvani K.,Imperial College London
Hematology / the Education Program of the American Society of Hematology. American Society of Hematology. Education Program | Year: 2011

Allogeneic hematopoietic stem cell transplantation (allogeneic HSCT) remains a curative treatment for hematological malignancies resistant to other treatment approaches through the unique GVL effect. However, relapse remains a major cause of treatment failure after allogeneic HSCT for patients with high-risk hematological malignancies. Further improvements in exploiting the GVL effect to prevent relapse in high-risk leukemias while minimizing toxicity have focused on the use of targeted antileukemic immunotherapy. These strategies include methods to boost the GVL effect with leukemia vaccines or the adoptive transfer of leukemia-specific lymphocytes. Vaccines can be classified as those against defined antigens such as minor histocompatibility antigens (mHags) or leukemia-associated antigens (PR1, WT1, and BCR-ABL) and those that have broad "antileukemic" activity such as engineered irradiated leukemia cells or leukemia-derived dendritic cells (DCs). The unique posttransplantation milieu, which is characterized by lymphopenia, regulatory T-cell depletion, and the release of growth factors, provides a unique opportunity for effective antitumor immunotherapy and augmenting specific GVL responses. This review focuses on approaches to enhancimg the GVL response by combining allogeneic HSCT with vaccination. Source

Barnes P.J.,Imperial College London
Journal of Allergy and Clinical Immunology | Year: 2013

Reduced responsiveness to the anti-inflammatory effects of corticosteroids is a major barrier to effective management of asthma in smokers and patients with severe asthma and in the majority of patients with chronic obstructive pulmonary disease (COPD). The molecular mechanisms leading to steroid resistance are now better understood, and this has identified new targets for therapy. In patients with severe asthma, several molecular mechanisms have been identified that might account for reduced steroid responsiveness, including reduced nuclear translocation of glucocorticoid receptor (GR) α after binding corticosteroids. This might be due to modification of the GR by means of phosphorylation as a result of activation of several kinases (p38 mitogen-activated protein kinase α, p38 mitogen-activated protein kinase γ, and c-Jun N-terminal kinase 1), which in turn might be due to reduced activity and expression of phosphatases, such as mitogen-activated protein kinase phosphatase 1 and protein phosphatase A2. Other mechanisms proposed include increased expression of GRβ, which competes with and thus inhibits activated GRα; increased secretion of macrophage migration inhibitory factor; competition with the transcription factor activator protein 1; and reduced expression of histone deacetylase (HDAC) 2. HDAC2 appears to mediate the action of steroids to switch off activated inflammatory genes, but in patients with COPD, patients with severe asthma, and smokers with asthma, HDAC2 activity and expression are reduced by oxidative stress through activation of phosphoinositide 3-kinase δ. Strategies for managing steroid resistance include alternative anti-inflammatory drugs, but a novel approach is to reverse steroid resistance by increasing HDAC2 expression, which can be achieved with theophylline and phosphoinositide 3-kinase δ inhibitors. Long-acting β2-agonists can also increase steroid responsiveness by reversing GRα phosphorylation. Identifying the molecular mechanisms of steroid resistance in asthmatic patients and patients with COPD can thus lead to more effective anti-inflammatory treatments. © 2013 American Academy of Allergy, Asthma & Immunology. Source

Whittaker A.C.,Imperial College London
Lithosphere | Year: 2012

The Earth's surface is shaped by tectonics and climate. This simple statement implies that we should, in principle, be able to use the landscape as an archive of both tectonic rates and of changes to climate regime. To solve this inverse problem, and decipher the geomorphic record effectively, we need a sound understanding of how landscapes respond and erode in response to changes in tectonic or climatic boundary conditions. Rivers have been a major focus of research in this fi eld because they are patently sensitive to tectonic and climatic forcing via their channel gradient and discharge. Theoretical, fi eld, and numerical modeling techniques in the last few years have produced a wealth of insight into the behavior of fl uvial landscapes, while the increasing availability of high-resolution topographic models have provided the data sets necessary to address this research challenge across the globe. New work by Miller et al. (2012) in Papua New Guinea highlights the progress we have made in extracting tectonics from topography due to these developments, but also illustrates the problems that still remain. This paper reviews our current knowledge of how fl uvial landscapes record tectonics at topographic steady-state and under "transient" conditions, assesses why the climate signal has proven so challenging to interpret, and maps out where we need to go in the future. © 2012 Geological Society of America. Source

Sephton M.A.,Imperial College London
Geochimica et Cosmochimica Acta | Year: 2013

Ancient meteorites contain several percent of organic matter that represents a chronicle of chemical evolution in the early solar system. Aromatic hydrocarbon units make up the majority of meteorite organic matter but reading their record of organic evolution is not straightforward and their formation mechanisms have remained elusive. Most aromatic units reside in a macromolecular material and new perceptions of its structure have been provided by a novel on-line hydrogenation approach. When applied to the Orgueil (CI1) and Murchison (CM2) meteorites the technique releases a range of aromatic hydrocarbons along with some oxygen, sulphur and nitrogen-containing aromatic units. When on-line hydrogenation is compared to conventional pyrolysis, more high molecular weight units and a wider range of liberated entities are evident. Comparisons of results from Orgueil and Murchison reveal variations that are most likely related to differing levels of parent body alteration. The enhancement of straight-chain hydrocarbons (n-alkanes) in the hydrogenation products imply a source of these common contaminants from straight-chain carboxylic acid (n-alkanoic acid) precursors, perhaps from bacterial contributions on Earth. The on-line hydrogenation data also highlight a long-standing but unexplained observation related to the relative preference for specific isomers in methyl-substituted benzenes (meta-, ortho- and para-xylenes). The new hydrogenation approach appears to release and transform macromolecular material meta-structures (benzenes with substituents separated by single carbon atoms) into their free hydrocarbon counterparts. Their release characteristics suggest that the meta-structures are bound by oxygen-linkages. The meta-structures may be molecular probes of specific ancient cosmic environments. Parent body processing may have performed a similar function as hydrogenation to produce the most common meta configuration for free substituted benzenes. Notably, this isomeric preference for substituted benzenes is relatively distinctive for meteorites and can help in the discrimination of meteorite-derived and fossil biology-derived organic matter on Earth and on Mars. © 2013 Elsevier Ltd. Source

Prospective studies have consistently reported lower colorectal cancer risks associated with higher intakes of total dairy products, total milk and dietary calcium. However, less is known about whether the inverse associations vary for individual dairy products with differing fat contents. In the European Prospective Investigation into Cancer and Nutrition (EPIC), we investigated the associations between intakes of total milk and milk subtypes (whole-fat, semi-skimmed and skimmed), yoghurt, cheese, and dietary calcium with colorectal cancer risk amongst 477,122 men and women. Dietary questionnaires were administered at baseline. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models, adjusted for relevant confounding variables. During the mean 11 years of follow-up, 4,513 incident cases of colorectal cancer occurred. After multivariable adjustments, total milk consumption was inversely associated with colorectal cancer risk (HR per 200 g/day 0.93, 95% CI: 0.89-0.98). Similar inverse associations were observed for whole-fat (HR per 200 g/day 0.90, 95% CI: 0.82-0.99) and skimmed milk (HR per 200 g/day 0.90, 95% CI: 0.79-1.02) in the multivariable models. Inverse associations were observed for cheese and yoghurt in the categorical models; although in the linear models, these associations were non-significant. Dietary calcium was inversely associated with colorectal cancer risk (HR per 200 mg/day 0.95, 95% CI: 0.91-0.99); this association was limited to dairy sources of calcium only (HR per 200 mg/day 0.95, 95% CI: 0.91-0.99), with no association observed for non-dairy calcium sources (HR per 200 mg/day 1.00, 95% CI: 0.81-1.24). Our results strengthen the evidence for a possible protective role of dairy products on colorectal cancer risk. The inverse associations we observed did not differ by the fat content of the dairy products considered. Source

Soto D.,Imperial College London | Silvanto J.,University of Westminster | Silvanto J.,Aalto University
Trends in Cognitive Sciences | Year: 2014

Classically, the operation of working memory (WM) has been strongly coupled with conscious states; it is thought that WM operates on conscious input and that we are conscious of the contents and operations of WM. Here, we re-evaluate the relationship between WM and conscious awareness in light of current data and question the views that awareness is mandatory for the operation of WM and that WM contents are necessarily linked to experiential states that are consciously accessible for perceptual report. We propose a novel framework for the relationship between WM and conscious awareness. © 2014 Elsevier Ltd. Source

Grimm S.,Imperial College London
Biochimica et Biophysica Acta - Bioenergetics | Year: 2013

I review here the evidence that complex II of the respiratory chain (RC) constitutes a general sensor for apoptosis induction. This concept emerged from work on neurodegenerative diseases and from recent data on metabolic alterations in cancer cells affecting the RC and in particular on mutations of complex II subunits. It is also supported by experiments with many anticancer compounds that compared the apoptosis sensitivities of complex II-deficient versus WT cells. These results are explained by the mechanistic understanding of how complex II mediates the diverse range of apoptosis signals. This protein aggregate is specifically activated for apoptosis by pH change as a common and early feature of dying cells. This leads to the dissociation of its SDHA and SDHB subunits from the remaining membrane-anchored subunits and the consequent block of it enzymatic SQR activity, while its SDH activity, which is contained in the SDHA/SDHB subcomplex, remains intact. The uncontrolled SDH activity then generates excessive amounts of reactive oxygen species for the demise of the cell. Future studies on these mitochondrial processes will help refine this model, unravel the contribution of mutations in complex II subunits as the cause of degenerative neurological diseases and tumorigenesis, and aid in discovering novel interference options. This article is part of a Special Issue entitled: Respiratory complex II: Role in cellular physiology and disease. © 2012 Elsevier B.V. Source

Barnes P.J.,Imperial College London
Medical Principles and Practice | Year: 2010

Chronic obstructive pulmonary disease (COPD) is a major global health problem which is increasing throughout the world and a major cause of death. However, current therapies fail to prevent disease progression or mortality. The mainstay of current drug therapy are long-acting bronchodilators; several longer-acting inhaled β2-agonists and muscarinic antagonists (and combinations) are now in development. No treatments have so far been shown to suppress chronic inflammation in COPD lungs. With better understanding of the inflammatory and destructive process in the pathophysiology of COPD, several new targets have been identified. Several mediator antagonists tested in COPD have so far been disappointing, but CXCR2 antagonists that block pulmonary neutrophil and monocyte recruitment may be more promising. Broad-spectrum anti-inflammatory drugs may be more effective, and include inhibitors of the enzymes phosphodiesterase-4, p38 mitogen-activated protein kinase, NF-κB kinase and phosphoinositide 3 kinase-γ and -δ, but side effects will be a major limitation so that inhaled delivery may be necessary. Perhaps the most promising approach is reversal of corticosteroid resistance through increasing histone deacetylase-2 activity. This might be achieved by theophylline-like drugs, phosphoinositide 3 kinase-δ inhibitors, more effective antioxidants and non-antibiotic macrolides. © 2010 S. Karger AG. Source

Drumright L.N.,Imperial College London
Sexually transmitted infections | Year: 2010

To test the use of a rapid assessment tool to determine social network size, and to test whether social networks with a high density of HIV/sexually transmitted infection (STI) or substance using persons were independent predictors of HIV and STI status among men who have sex with men (MSM) using a rapid tool for collecting network information. We interviewed 609 MSM from 14 bars in San Diego, California, USA, using an enhanced version of the Priorities for Local AIDS Control Efforts (PLACE) methodology. Social network size was assessed using a series of 19 questions of the form 'How many people do you know that have the name X?', where X included specific male and female names (eg, Keith), use illicit substances, and have HIV. Generalised linear models were used to estimate average and group-specific network sizes, and their association with HIV status, STI history and methamphetamine use. Despite possible errors in ascertaining network size, average reported network sizes were larger for larger groups. Those who reported having HIV infection or having past STI reported significantly more HIV infected and methamphetamine or popper using individuals in their social network. There was a dose-dependent effect of social network size of HIV infected individuals on self-reported HIV status, past STI and use of methamphetamine in the last 12 months, after controlling for age, ethnicity and numbers of sexual partners in the last year. Relatively simple measures of social networks are associated with HIV/STI risk, and may provide a useful tool for targeting HIV/STI surveillance and prevention. Source

Ashton-Rickardt P.G.,Imperial College London
Immunology Letters | Year: 2013

Serine proteases control a wide variety of physiological and pathological processes in multi-cellular organisms, including blood clotting, cancer, cell death, osmo-regulation, tissue re-modeling and immunity to infection. T lymphocytes are required for adaptive cell mediated immunity and serine proteases are not only important for effector function but also homeostatic regulation of cell numbers. Serine Protease Inhibitor. s (Serpins) are the physiological regulators of serine proteases activity. In this review, I will discuss the role of serpins in controlling the recognition of antigen, effector function and homeostatic control of T lymphocytes through the inhibition of physiological serine protease targets. An emerging view of serpins is that they are important promoters of cellular viability through their inhibition of executioner proteases. This will be discussed in the context of the T lymphocyte survival during effector responses and the development and persistence of long-lived memory T cells. The potent anti-apoptotic properties of serpins can also work against adaptive cell immunity by protecting viruses and tumors from eradication by cytotoxic T cells (CTL). Recent insights from knock-out mouse models demonstrate that these serpins also are required for hematological progenitor cells and so are critical for the development of lineages other than T lymphocytes. Given the emerging role of serpins in multiple aspects of lymphocyte immunity and blood development I will review the progress to date in developing new immunotherapeutic approaches based directly on serpins or knowledge gained from identifying their physiologically relevant protease targets. © 2013 Elsevier B.V. Source

Bures J.,Imperial College London
Angewandte Chemie - International Edition | Year: 2016

A graphical analysis to elucidate the order in catalyst is presented. This analysis uses a normalized time scale, t[cat]T n, to adjust entire reaction profiles constructed with concentration data. The method is fast and simple to perform because it directly uses the concentration data, therefore avoiding the data handling that is usually required to extract rates. Compared to methods that use rates, the normalized time scale analysis requires fewer experiments and minimizes the effects of experimental errors by using information on the entire reaction profile. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Poulter N.R.,Imperial College London | Prabhakaran D.,Center for Chronic Disease Control | Caulfield M.,Queen Mary, University of London
The Lancet | Year: 2015

Raised blood pressure is the biggest single contributor to the global burden of disease and to global mortality. The numbers of people affected and the prevalence of high blood pressure worldwide are expected to increase over the next decade. Preventive strategies are therefore urgently needed, especially in less developed countries, and management of hypertension must be optimised. Genetic advances in some rare causes of hypertension have been made lately, but the aggregate effect on blood pressure of all the genetic loci identified to date is small. Hence, intervention on key environmental determinants and effective implementation of trial-based therapies are needed. Three-drug combinations can control hypertension in about 90% of patients but only if resources allow identification of patients and drug delivery is affordable. Furthermore, assessment of optimal drug therapy for each ethnic group is needed. © 2015 Elsevier Ltd. Source

McNab F.,Glaxosmithkline | McNab F.,UK National Institute for Medical Research | Mayer-Barber K.,National Institute of Allergy and Infectious Diseases | Sher A.,National Institute of Allergy and Infectious Diseases | And 3 more authors.
Nature Reviews Immunology | Year: 2015

Type I interferons (IFNs) have diverse effects on innate and adaptive immune cells during infection with viruses, bacteria, parasites and fungi, directly and/or indirectly through the induction of other mediators. Type I IFNs are important for host defence against viruses. However, recently, they have been shown to cause immunopathology in some acute viral infections, such as influenza virus infection. Conversely, they can lead to immunosuppression during chronic viral infections, such as lymphocytic choriomeningitis virus infection. During bacterial infections, low levels of type I IFNs may be required at an early stage, to initiate cell-mediated immune responses. High concentrations of type I IFNs may block B cell responses or lead to the production of immunosuppressive molecules, and such concentrations also reduce the responsiveness of macrophages to activation by IFNγ, as has been shown for infections with Listeria monocytogenes and Mycobacterium tuberculosis. Recent studies in experimental models of tuberculosis have demonstrated that prostaglandin E2 and interleukin-1 inhibit type I IFN expression and its downstream effects, demonstrating that a cross-regulatory network of cytokines operates during infectious diseases to provide protection with minimum damage to the host. © 2015 Macmillan Publishers Limited. All rights reserved. Source

Elkeles R.S.,Imperial College London
Atherosclerosis | Year: 2010

Measurement of coronary artery calcium score (CACS) by electron beam tomography has been shown to a powerful predictor of coronary heart disease events in asymptomatic non-diabetic subjects. In type 2 diabetes, measurement of CACS was found to be a powerful predictor of cardiovascular events which could enhance prediction provided by established risk models. 23% of type 2 diabetic subjects with low CACS were found to be at low risk for cardiovascular events. Moreover mortality was similar for type 2 diabetic and non-diabetic subjects with undetectable coronary artery calcification. Conversely type 2 diabetic subjects with high CACS were identified who were at high cardiovascular risk. Thus not all those with type 2 diabetes are at similar cardiovascular risk. Measurement of CACS enables cardiovascular risk in type 2 diabetes to be stratified so that the level of preventive therapy could be reduced in some and intensified in others. Although prospective data for the power of CACS to predict CHD events in type 1 diabetes are lacking, measurement of CACS could help in deciding on preventive therapy in type 1 diabetes. © 2009 Elsevier Ireland Ltd. Source

Hoskins B.,Imperial College London | Hoskins B.,University of Reading
Quarterly Journal of the Royal Meteorological Society | Year: 2013

Predictability is considered in the context of the seamless weather-climate prediction problem, and the notion is developed that there can be predictive power on all timescales. On all scales there are phenomena that occur as well as longer time-scales and external conditions that should combine to give some predictability. To what extent this theoretical predictability may actually be realised and, further, to what extent it may be useful is not clear. However the potential should provide a stimulus to, and high profile for, our science and its application for many years. © 2012 Royal Meteorological Society. Source

Shi W.,Imperial College London
Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention | Year: 2012

Non-rigid image registration using free-form deformations (FFD) is a widely used technique in medical image registration. The balance between robustness and accuracy is controlled by the control point grid spacing and the amount of regularization. In this paper, we revisit the classic FFD registration approach and propose a sparse representation for FFDs using the principles of compressed sensing. The sparse free-form deformation model (SFFD) can capture fine local details such as motion discontinuities without sacrificing robustness. We demonstrate the capabilities of the proposed framework to accurately estimate smooth as well as discontinuous deformations in 2D and 3D image sequences. Compared to the classic FFD approach, a significant increase in registration accuracy can be observed in natural images (61%) as well as in cardiac MR images (53%) with discontinuous motions. Source

Graefe E.-M.,Imperial College London
Journal of Physics A: Mathematical and Theoretical | Year: 2012

The understanding of nonlinear PT symmetric quantum systems, arising for example in the theory of Bose-Einstein condensates in PT symmetric potentials, is widely based on numerical investigations, and little is known about generic features induced by the interplay of PT symmetry and nonlinearity. To gain deeper insights it is important to have analytically solvable toy models at hand. In the present paper the stationary states of a simple toy model of a PT symmetric system previously introduced in [1, 2] are investigated. The model can be interpreted as a simple description of a Bose-Einstein condensate in a PT symmetric double well trap in a two-mode approximation. The eigenvalues and eigenstates of the system can be explicitly calculated in a straightforward manner; the resulting structures resemble those that have recently been found numerically for a more realistic PT symmetric double delta potential. In addition, a continuation of the system is introduced that allows an interpretation in terms of a simple linear matrix model. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to Quantum physics with non-Hermitian operators. © 2012 IOP Publishing Ltd. Source

Young A.H.,Imperial College London
Journal of psychopharmacology (Oxford, England) | Year: 2013

Bipolar disorder is a chronic mental illness associated with high levels of somatic morbidity, comorbidity and mortality. Treatment guidelines for bipolar mania generally recommend initiating first-line therapy with a second-generation antipsychotic or mood stabiliser, either alone or in combination. Asenapine is a second-generation antipsychotic with a unique receptor binding profile, licensed for the treatment of manic episodes in adults with bipolar I disorder. 'Real-world' data are needed to complement evidence from clinical trials, in order to provide clinicians with pragmatic information regarding the likely risks and benefits of using a new agent in clinical practice. Evidence from real-world case reports demonstrates that - as in clinical trials - asenapine is effective in treating mania and mixed episodes associated with bipolar I disorder, whether used as monotherapy or in combination with a mood stabiliser. It has a rapid onset of antimanic effect and an early improvement is associated with treatment outcome. Asenapine also shows promise in controlling depressive symptoms and clinically challenging mixed states. Asenapine has a favourable tolerability profile, compared with other first-line agents, having a minimal impact on weight and metabolic parameters. Asenapine should be considered a first-line treatment option for adults with bipolar I disorder. Source

The Irish and British governments have recently mandated the replacement of domestic gas and electricity meters with smart meters. Their deployment strategies differ based on the extent to which deregulation of the gas and electricity market has been successful. A broad debate has been held on the various assumptions justifying the cost-benefit analyses and the permutations of these assumptions. What has been paid less attention is to what end is a smart meter being employed towards. A corollary research question is whether the deployment plan is targeting the correct sector.If the purpose is to introduce automated meter reading across the housing sector then a better strategy would be to legislate for accurate monthly bills, as in Sweden. Allowing suppliers to have greater flexibility will likely reward rather than stifle the design of competition. If the purpose is to manage demand then it may be that it's working with complex tariffs and not the meter per se that counts. The high consuming end-use categories and profile classes would be better placed for that exercise. Innovation theory also supports the targeting of new innovations to larger consumers, allowing metering innovations to proceed along historical trajectories. © 2013 Elsevier Ltd. Source

Jawad M.,Imperial College London
Nicotine and Tobacco Research | Year: 2014

Introduction: Waterpipe tobacco smoking (WTS) is prevalent worldwide and is legislatively enforceable under many countries' existing tobacco laws. Globally, however, the waterpipe tobacco industry anecdotally appears poorly controlled. This study aimed to gather intelligence from local government (known as local authority [LA]) staff in London, United Kingdom, about their WTS enforcement experiences. Methods: In-depth telephone interviews were conducted among 26 LA staff from 14 London boroughs, exploring industry characteristics and tobacco legislation compliance. Recurrent themes were analyzed and derived deductively. Results: Approximately 400 waterpipe premises operate across London, benefiting from high profit margins. LA staff are resource strained, limiting their surveillance of waterpipe premises, some of which are associated with an "underground" culture. Noise and nuisance are key features of waterpipe premises. Most waterpipe premises were generally noncompliant with most aspects of existing tobacco legislation, mainly due to disproportionately low fines and unclear legislation enforcement guidance. Successful methods for enforcing legislation included a synchronized, multiagency approach; however, this was inconsistently implemented across boroughs. Many LA staff believe licensing waterpipe premises will improve surveillance and control the industry's proliferation. Conclusions: The waterpipe tobacco industry is unregulated and places a significant burden on many LAs in London, mainly due to lack of resources. These problems may also occur in other large cities worldwide. Existing tobacco legislation should be amended to accommodate WTS, including consideration of licensing the industry. More research is needed to gain a full understanding of the waterpipe tobacco industry and its impact on other global cities. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. Source

Masters A.,Imperial College London
Journal of Geophysical Research A: Space Physics | Year: 2015

What we know about the magnetosphere of the outermost planet, Neptune, is primarily based on data taken during the Voyager 2 flyby in 1989. Establishing how Neptune's magnetosphere interacts with the solar wind is crucial for understanding the dynamics of the system. Here we assess how magnetic reconnection couples the solar wind to Neptune's magnetosphere, using analytical modeling that was recently applied to the case of Uranus. The modeling suggests that typical near-Neptune solar wind parameters make conditions at Neptune's magnetopause less favorable for magnetic reconnection than at the magnetopause boundary of any other solar system magnetosphere. The location of reconnection sites on Neptune's magnetopause is expected to be highly sensitive to planetary longitude and season, as well as interplanetary magnetic field (IMF) orientation, which is similar to the situation at Uranus. Also similar to past Uranus results, the present Neptune modeling indicates a seasonal effect, where one of the two dominant (Parker spiral) IMF orientations produces more favorable conditions for magnetopause reconnection than the other near equinox. We estimate the upper limit of the reconnection voltage applied to Neptune's magnetosphere as 35 kV (the typical voltage is expected to be considerably lower). Further progress in understanding the solar wind-magnetosphere interaction at Neptune requires other coupling mechanisms to be considered, as well as how reconnection operates at high plasma β. ©2014. American Geophysical Union. All Rights Reserved. Source

Muller E.A.,Imperial College London
Current Opinion in Chemical Engineering | Year: 2013

Although carbon is generally considered hydrophobic and a poor choice to fabricate membranes, recent developments in nanotechnology have provided nanoporous structures such as nanotubes and graphene sheets, which hold promise as the 'ultimate' membrane materials for water purification. Nonetheless, the behaviour of water through these nanoconfined environments is unique and nonintuitive. This review describes our current understanding and challenges associated with the molecular simulation of the water-carbon interaction. It is expected that simulations can guide the design of water purification membranes with both high selectivity and high permeability. © 2013 Elsevier Ltd. Source

Milner-Gulland E.J.,Imperial College London
Proceedings of the National Academy of Sciences of the United States of America | Year: 2011

Natural resource management is littered with cases of overexploitation and ineffectual management, leading to loss of both biodiversity and human welfare. Disciplinary boundaries stifle the search for solutions to these issues. Here, I combine the approach of management strategy evaluation, widely applied in fisheries, with household utility models from the conservation and development literature, to produce an integrated framework for evaluating the effectiveness of competing management strategies for harvested resources against a range of performance metrics. I demonstrate the strengths of this approach with a simple model, and use it to examine the effect of manager ignorance of household decisions on resource management effectiveness, and an allocation tradeoff between monitoring resource stocks to reduce observation uncertainty and monitoring users to improve compliance. I show that this integrated framework enables management assessments to consider household utility as a direct metric for system performance, and that although utility and resource stock conservation metrics are well aligned, harvest yield is a poor proxy for both, because it is a product of household allocation decisions between alternate livelihood options, rather than an end in itself. This approach has potential far beyond single-species harvesting in situations where managers are in full control; I show that the integrated approach enables a range of management intervention options to be evaluated within the same framework. Source

Auner H.W.,Imperial College London | Cenci S.,Vita-Salute San Raffaele University
British Journal of Haematology | Year: 2015

Multiple myeloma is a genetically heterogeneous tumour of transformed plasma cells, terminally differentiated effectors of the B cell lineage specialized in producing large amounts of immunoglobulins. The uniquely well-developed secretory apparatus that equips normal and transformed plasma cells with the capacity for high-level protein secretion constitutes a distinctive therapeutic target. In this review we discuss how fundamental cellular processes, such as the unfolded protein response (UPR), endoplasmic reticulum (ER)-associated degradation and autophagy, maintain intracellular protein homeostasis (proteostasis) and regulate plasma cell ontogeny and malignancy. We summarize our current understanding of the cellular effects of proteasome inhibitors and the molecular bases of resistance to them. Furthermore, we discuss how improvements in our understanding of the secretory apparatus and of the complex interactions between intracellular protein synthesis and degradation pathways can disclose novel drug targets for multiple myeloma, defining a paradigm of general interest for cancer biology and disorders of altered proteostasis. © 2014 John Wiley & Sons Ltd. Source

Shaik S.,Hebrew University of Jerusalem | Rzepa H.S.,Imperial College London | Hoffmann R.,Cornell University
Angewandte Chemie - International Edition | Year: 2013

What could be simpler than C2, a diatomic molecule that has the second strongest homonuclear bond? This molecule turns out to be a microcosm of the bonding issues that bother chemists, as is shown in this trialogue. Join the three authors in their lively debate, light a candle, as Faraday did, and see the excited states of C2! Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Rutter G.A.,Imperial College London | Chimienti F.,Astrazeneca
Diabetologia | Year: 2015

SLC30A8 encodes the secretory granule-resident and largely endocrine pancreas-restricted zinc transporter ZnT8. Interest in this gene product was sparked amongst diabetologists in 2007 when the first genome-wide association study for type 2 diabetes identified polymorphisms in SLC30A8 as affecting disease risk. Thus, the common polymorphism rs13266634 was associated with lowered beta cell function and a 14% increase in diabetes abundance per risk (C) allele. This non-synonymous variant encodes a tryptophan-to-arginine switch at position 325 in the protein’s intracellular carboxy-terminal domain, resulting in reduced zinc transport activity and, consequently, decreased intragranular zinc levels. Whereas insulin secretion from isolated islets is most often increased in mice inactivated for Slc30a8, null animals usually show impaired glucose tolerance and lowered circulating insulin. Since Slc30a8 null animals display little, if any, zinc secretion from islets, the lower plasma insulin levels could be explained by increased hepatic clearance as a result of lowered local zinc levels, or less efficient insulin action on target tissues. Despite the emerging consensus on the role of ZnT8 in glucose homeostasis, a recent genetic study in humans has unexpectedly identified loss-of-function SLC30A8 mutants that are associated with protection from diabetes. Here, we attempt to reconcile these apparently contradictory findings, implicating (1) differing degrees of inhibition of ZnT8 activity in carriers of common variants vs rare loss-of-function forms, (2) effects dependent on age or hypoxic beta cell stress. We propose that these variables conspire to affect both the size and the direction of the effect of SLC30A8 risk alleles in man. © 2014, Springer-Verlag Berlin Heidelberg. Source

Kon S.S.,Imperial College London
Expert review of respiratory medicine | Year: 2012

Acute exacerbations are major events in the natural history of chronic obstructive pulmonary disease (COPD) and are associated with increased morbidity and mortality. Although pulmonary rehabilitation increases exercise capacity, reduces dyspnea and improves health-related quality of life, the effects on risk of future exacerbations (and by extension, healthcare utilization) are less well documented. Furthermore, there has been a growing evidence base to support provision of pulmonary rehabilitation in the acute phase of COPD, for example, shortly after hospitalization for an acute exacerbation. This article reviews the role of pulmonary rehabilitation in the prevention and treatment of acute exacerbations of COPD. Source

Dimopoulos K.,Imperial College London
European Respiratory Review | Year: 2013

This is the case of a young female who was seen at our adult congenital heart disease and pulmonary hypertension service (Royal Brompton Hospital, London, UK) at the age of 17 years. She initially presented at the age of 4 years with increasing shortness of breath. At that time, there was differential cyanosis with clubbing and lower oxygen saturations in the toes (82%) compared with her fingers (95%). On echocardiography there was evidence of severe pulmonary hypertension and a large patent ductus arteriosus (PDA) with low velocity bidirectional shunting. She underwent cardiac catheterisation at the time which showed a pulmonary arterial pressure equal to that of the aorta. © ERS 2013. Source

Brusamento S.,Imperial College London
Cochrane database of systematic reviews (Online) | Year: 2012

Despite efforts to increase the uptake of prevention of mother to child transmission of HIV (PMTCT) services, coverage is still lower than desired in developing countries. A lack of male partner involvement in PMTCT services is a major barrier for women to access these services. To evaluate the impact of interventions which aim to enhance male involvement to increase women's uptake of PMTCT interventions in developing countries. We searched the following databases from the year 2000 to November 2011: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, the WHO Global Health Library, ClinicalTrials.gov, Current Controlled Trials, AEGIS, CROI, IAS, IAC web sites. We included randomised controlled trials (RCTs), cluster-randomised controlled trials, quasi-randomised controlled trials, controlled before and after studies and interrupted time series studies assessing interventions to increase male involvement for improvement of uptake PMTCT services in low- and middle-income countries.. Two reviewers independently searched, screened, assessed study quality and extracted data. A third reviewer resolved any disagreement. Only one study met the inclusion criteria, an RCT conducted in Tanzania between May 2003 and October 2004. Women in the intervention group (n=760) received a letter for their male partners, which invited them to return together to receive Couple Voluntary Counselling and Testing (CVCT) for HIV. Women in the control group (n=761) received individual HIV VCT during their first ANC visit and then usual care. The percentages of women who received HIV VCT and collected their results were 48%, 45% and 39% in the intervention group and 93%, 78% and 71% in the control group (p <0,001). Only 33% of women in the intervention group returned with their male partners and only 47% of them went through the whole CVCT process. The proportion of women who received HIV prophylaxis at delivery was not different between the two arms (27% in the intervention and 22% in the control group). The study had a high risk of bias.   We found only one eligible study that assessed the effectiveness of male involvement in improving women's uptake of PMTCT services, which only focused on one part of the perinatal PMTCT cascade. We urgently need more rigorously designed studies assessing the impact of male engagement interventions on women's uptake of PMTCT services to know if this intervention can contribute to improve uptake of PMTCT services and reduce vertical transmission of HIV in children.    Source

Arias A.C.,Palo Alto Research Center PARC | MacKenzie J.D.,Green Hills | McCulloch I.,Imperial College London | Rivnay J.,Stanford University | Salleo A.,Stanford University
Chemical Reviews | Year: 2010

The synthesis, processing, and device performance of polymeric semiconductors has been reported. The polysilicon TFT technology is used for active matrix organic light-emitting diode (AMOLED) as the higher carrier mobilities of polysilicon as compared to a-Si, and increased stability of polysilicon-based devices under bias stress, are more effective in AMOLED. The radio frequency (RF) wireless applications are required in large area, self-powered, or maximized range device is partially driven by the fundamental physics of the frequency regimes in which they operate. Large area, high throughput manufacturing of organic electronic roducts is most efficiently enabled by solution based, additive printing techniques. Regioregular (RR) poly(3-hexylthiophene) (P3HT) is an exemplary semiconducting polymer due to its ready availability, ease of processing from solution, and its promising electrical properties arising from a highly crystalline microstructure. Source

Jones H.F.,Imperial College London
Journal of Physics A: Mathematical and Theoretical | Year: 2012

Propagation of light through a medium with a complex refractive index in which gain and loss are engineered to be PT symmetric has many remarkable features. In particular the usual unitarity relations are not satisfied, so that the reflection coefficients can be greater than 1, and in general are not the same for left or right incidence. Within the class of optical potentials of the form v(x) = v 1cos(2βx) + iv 2sin(2βx) the case v 2 = v 1 is of particular interest, as it lies on the boundary of PT-symmetry breaking. It has been shown in a recent paper by Lin et al that in this case one has the property of unidirectional invisibility, while for propagation in the other direction there is a greatly enhanced reflection coefficient proportional to L 2, where L is the length of the medium in the direction of propagation. For this potential we show how analytic expressions can be obtained for the various transmission and reflection coefficients, which are expressed in a very succinct form in terms of modified Bessel functions. While our numerical results agree very well with those of Lin et al we find that the invisibility is not quite exact, in amplitude or phase. As a test of our formulas we show that they identically satisfy a modified version of unitarity appropriate for PT-symmetric potentials. We also examine how the enhanced transmission comes about for a wave packet, as opposed to a plane wave, finding that the enhancement now arises through an increase, of O(L), in the pulse length, rather than the amplitude. © 2012 IOP Publishing Ltd. Source

Hillary R.M.,Imperial College London
Biometrics | Year: 2011

The vast majority of population models work using age or stage not length but there are many cases where animals cannot be aged sensibly or accurately. For these cases length-based models form the logical alternative but there has been little work done to develop and compare different methods of estimating growth transition matrices to be used in such models. This article demonstrates how a consistent Bayesian framework for estimating growth parameters and a novel method for constructing length transition matrices accounts for variation in growth in a clear and consistent manner and avoids potential subjective choices required using more established methods. The inclusion of the resultant growth uncertainty in population assessment models and the potential impact on management decisions is also addressed. © 2010, The International Biometric Society. Source

Chatzis S.P.,Imperial College London
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2010

Hidden Markov models (HMMs) are a popular approach for modeling sequential data comprising continuous attributes. In such applications, the observation emission densities of the HMM hidden states are typically modeled by means of elliptically contoured distributions, usually multivariate Gaussian or Student's-t densities. However, elliptically contoured distributions cannot sufficiently model heavy-tailed or skewed populations which are typical in many fields, such as the financial and the communication signal processing domain. Employing finite mixtures of such elliptically contoured distributions to model the HMM state densities is a common approach for the amelioration of these issues. Nevertheless, the nature of the modeled data often requires postulation of a large number of mixture components for each HMM state, which might have a negative effect on both model efficiency and the training data set's size required to avoid overfitting. To resolve these issues, in this paper, we advocate for the utilization of a nonelliptically contoured distribution, the multivariate normal inverse Gaussian (MNIG) distribution, for modeling the observation densities of HMMs. As we experimentally demonstrate, our selection allows for more effective modeling of skewed and heavy-tailed populations in a simple and computationally efficient manner. © 2010 IEEE. Source

Anie K.A.,Imperial College London
Cochrane database of systematic reviews (Online) | Year: 2012

Sickle cell disease comprises a group of genetic blood disorders. It occurs when the sickle haemoglobin gene is inherited from both parents. The effects of the condition are: varying degrees of anaemia which, if severe, can reduce mobility; a tendency for small blood capillaries to become blocked causing pain in muscle and bone commonly known as 'crises'; damage to major organs such as the spleen, liver, kidneys, and lungs; and increased vulnerability to severe infections. There are both medical and non-medical complications, and treatment is usually symptomatic and palliative in nature. Psychological interventions for individuals with sickle cell disease might complement current medical treatment, and studies of their efficacy have yielded encouraging results. To examine the evidence that psychological interventions improve the ability of people with sickle cell disease to cope with their condition. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, which comprises references identified from comprehensive electronic database searches and the Internet, handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search of the Group's Haemoglobinopathies Trials Register: 28 July 2011. All randomised or quasi-randomised controlled trials comparing psychological interventions with no (psychological) intervention in people with sickle cell disease. Both authors independently extracted data and assessed the risk of bias of the included studies. Eleven studies were identified in the searches and six of these were eligible for inclusion in the review. Four studies, involving 223 participants, provided data for analysis. One study showed that cognitive behaviour therapy significantly reduced the affective component of pain, mean difference -3.00 (95% confidence interval -4.63 to -1.37), but not the sensory component, mean difference 0.00 (95% confidence interval -9.39 to 9.39). One study of family psycho-education was not associated with a reduction in depression. Another study evaluating cognitive behavioural therapy had inconclusive results for the assessment of coping strategies, and showed no difference between groups assessed on health service utilisation. Evidence for the efficacy of psychological therapies in sickle cell disease is currently limited. This systematic review has clearly identified the need for well-designed, adequately-powered, multicentre randomised controlled trials assessing the effectiveness of specific interventions in sickle cell disease. Source

Zaki T.A.,Imperial College London
Flow, Turbulence and Combustion | Year: 2013

".an eerie type of chaos can lurk just behind a facade of order, and yet deep inside the chaos lurks an even eerier type of order." Douglas Hofstadter Bypass transition to turbulence in boundary layers is examined using linear theory and direct numerical simulations (DNS). First, the penetration of low-frequency free-stream disturbances into the boundary layer is explained using a model problem with two time scales, namely the shear and wall-normal diffusion. The simple model provides a physical understanding of the phenomenon of shear sheltering. The second stage in bypass transition is the amplification of streaks. Streak detection and tracking algorithms were applied to examine the characteristics of the streak population inside the boundary layer, beneath free-stream turbulence. It is demonstrated that simple statistical averaging masks the wealth of streak amplitudes in transitional flows, and in particular the high-amplitude, relatively rare events that precede the onset of turbulence. The third stage of the transition process, namely the secondary instability of streaks, is examined using secondary instability analysis. It is demonstrated that two types of instability are possible: An outer instability arises near the edge of the boundary layer on the lifted, low-speed streaks. An inner instability also exists, and has the appearance of a near-wall wavepacket. The stability theory is robust, and can predict the particular streaks which are likely to undergo secondary instability and break down in transitional boundary layers beneath free-stream turbulence. Beyond the secondary instability, turbulent spots are tracked in DNS in order to examine their characteristics in the subsequent non-linear stages of transition. At every stage, we compare the findings from linear theory to the empirical observations from direct solutions of the Navier-Stokes equations. The complementarity between the theoretical predictions and the computational experiments is highlighted, and it leads to a detailed view of the mechanics of transition. © 2013 Springer Science+Business Media Dordrecht. Source

Rudenko G.,Imperial College London
Essays in Biochemistry | Year: 2010

The African trypanosome Trypanosoma brucei is a unicellular parasite which causes African sleeping sickness. Transcription in African trypanosomes displays some unusual features, as most of the trypanosome genome is transcribed as extensive polycistronic RNA Pol II (polymerase II) transcription units that are not transcriptionally regulated. In addition, RNA Pol I is used for transcription of a small subset of protein coding genes in addition to the rDNA (ribosomal DNA). These Pol I-transcribed protein coding genes include the VSG (variant surface glycoprotein) genes. Although a single trypanosome has many hundreds of VSG genes, the active VSG is transcribed in a strictly monoalleleic fashion from one of approx. 15 telomeric VSG ESs (expression sites). Originally, it was thought that chromatin was not involved in the transcriptional control of ESs; however, this view is now being re-evaluated. It has since been shown that the active ES is depleted of nucleosomes compared with silent ESs. In addition, a number of proteins involved in chromatin remodelling or histone modification and which play a role in ES silencing {including TbISWI [T. brucei ISWI (imitation-switch protein)] and DOT1B} have recently been identified. Lastly, the telomere-binding protein TbRAP1 (T. brucei RAP1) has been shown to establish a repressive gradient extending from the ES telomere end up to the ES promoter. We still need to determine which epigenetic factors are involved in 'marking' the active ES as part of the counting mechanism of monoallelic exclusion. The challenge will come in determining how these multiple regulatory layers contribute to ES control. © 2010 Biochemical Society. Source

Khullar V.,Imperial College London
International Urogynecology Journal and Pelvic Floor Dysfunction | Year: 2012

Overactive bladder (OAB) is highly prevalent and associated with considerable impact on patient health-related quality of life (HRQoL). Assessment of HRQoL can reveal the burden of disease and post-intervention improvement. This review aims to highlight the importance of HRQoL assessment and outline the tools available for use in clinical trials and real-world clinical practice. A number of validated measures of HRQoL specific to OAB have been developed, offering greater sensitivity and responsiveness over generic instruments. These condition-specific, multi-dimensional and single-item global questionnaires are particularly useful for the multiple and varied symptoms of OAB, as they reflect the patient's needs, concerns and values. Measurements for lower urinary tract symptoms, e. g. bladder diaries, are being compared with HRQoL instruments to provide greater understanding of the disease and treatment from the patient's perspective. Therapeutic interventions to improve OAB symptoms should also be evaluated for their effect on the patient's HRQoL. © The International Urogynecological Association 2011. Source

Tyrer P.,Imperial College London
Personality and Mental Health | Year: 2015

Objective: The objective of this study is to examine the evidence for a new hypothesis explaining the relationship between personality and mental state disorders. Design: At present, the attribution of personality disorder as a primary diagnosis only applies to patients who are antisocial, and particularly regarded as psychopathic, as in these patients, the mental state disorder that are associated are regarded in many respects as atypical and not representative of other mental disorders. The case is made in this paper that personality dysfunction lies behind the persistence of all non-cognitive mental disorders and that our failure to recognise this follows from our collective refusal to assess personality status early in life. Method: Narrative review of relevant literature, which is limited as personality status is not often assessed early in life. Results: Support is adduced that personality dysfunction lies behind the persistence of all non-cognitive mental disorders (i.e. those that are not specifically neurodevelopmental and linked to cognitive impairment). The potential importance of this hypothesis is presented with regard to treatment and management strategy, emphasising that without specific intervention for personality dysfunction, many patients are destined for persistent morbidity. © 2014 John Wiley & Sons, Ltd. Source

Wimalasundera R.C.,Imperial College London
Seminars in Fetal and Neonatal Medicine | Year: 2010

The substantial increase in high order multiple pregnancies in the last two decades as a result of assisted reproductive techniques has necessitated the development of multifetal pregnancy reduction as a management tool to decrease fetal number and improve perinatal survival. The evidence in favour of reduction in pregnancies with more than four fetuses to twins is undisputed. Despite the recent improvements in expectant management of triplets with reasonable perinatal outcomes, the evidence suggests that reduction to twins significantly reduces the risk of preterm delivery without an increase in miscarriage rates. Recent advances in vascular-occlusive techniques have allowed the possibility of selective termination in monochorionic pregnancies in the presence of discordant anomalies or indeed multifetal reduction in non-trichorionic triplets, with radiofrequency ablation and cord occlusion appearing to be the most successful. However, the techniques vary in complexity and complication rates, which increase with gestation. Hence the need to refer these pregnancies early to specialist centres. © 2010 Elsevier Ltd. Source

Rankin S.M.,Imperial College London
Immunology Letters | Year: 2012

The adult bone contains a number of distinct populations of stem cells, including haematopoietic stem cells, mesenchymal stem cells, endothelial progenitor cells and fibrocytes. While haematopoietic stem cells are required to provide a lifelong supply of blood cells it is thought that the other populations of stem cells play a role in tissue regeneration and potentially disease. The chemokine CXCL12 is produced constitutively in the bone marrow and, acting . via CXCR4, is critical in maintaining HSPCs in a quiescent state and retaining all subsets of stem and progenitor cells in the bone marrow environment. The cytokine G-CSF, used clinically to mobilize haematopoietic stem cells for bone marrow transplants, activates the sympathetic nervous system and bone marrow macrophages to reduce the expression of CXCL12 by bone marrow stromal cells, thereby promoting the exit of haematopoietic stem cells from the bone marrow. Understanding the molecular mechanisms underlying G-CSF stimulated mobilization has led to development of CXCR4 antagonists as fast acting mobilizing agents for haematopoietic stem cells. Evidence now suggests that CXCR4 antagonists can similarly mobilize distinct subsets of progenitor cells, namely the endothelial progenitor cells and mesenchymal stem cells, but this requires conditioning of the bone marrow with VEGF rather than G-CSF. © 2012 Elsevier B.V.. Source

Barnes P.,Imperial College London
Seminars in Respiratory and Critical Care Medicine | Year: 2012

Current therapy for asthma with inhaled corticosteroids and long-acting inhaled β2-agonists is highly effective, safe, and relatively inexpensive, but many patients remain poorly controlled. Most advances have been through improving these drug classes and a major developmental hurdle is to improve existing drug classes. Major unmet needs include better treatment of severe asthma (which has some similarity to chronic obstructive pulmonary disease), as well as curative therapies for mild to moderate asthma that do not result in the return of symptoms when the treatment is stopped. Several new treatments are in development, but many are specific, targeting a single mediator or receptor, and are unlikely to have a major clinical impact, although they may be effective in specific asthma phenotypes (endotypes). Drugs with more widespread effects, such as kinase inhibitors, may be more effective but have a greater risk of side effects so inhaled delivery may be needed. Several new treatments target the underlying allergic/immune process and would treat concomitant allergic diseases. Improved immunotherapy approaches have the potential for disease modification, although prospects for a cure are currently remote. © Georg Thieme Verlag Stuttgart ·New York. Source

Trento C.,Imperial College London
Swiss medical weekly : official journal of the Swiss Society of Infectious Diseases, the Swiss Society of Internal Medicine, the Swiss Society of Pneumology | Year: 2010

The properties of mesenchymal stem cells (MSC) have been widely investigated during the last decade, from their differentiation capacity to their immunosuppressive effect on any type of immune cell. These properties have been successfully harnessed for the treatment of inflammatory diseases such as graft versus host disease (GvHD). Different mechanisms have been proposed for their immunosuppressive properties, although it seems likely that they are used in concert. The inflammatory environment to which MSC are exposed plays a pivotal role in activating their functions. Conversely, the interplay of MSC with the immunoregulatory networks recruited during inflammation is fundamental to the delivery of immunosuppression. Since other types of terminally differentiated stromal cells share these properties, it is plausible that stemness is not a required feature. Therefore these functions may be involved in the physiological control of acute inflammation in various tissues. These notions highlight the importance of investigating the role of stromal cells as modulators of immune responses. Source

Apperley J.F.,Imperial College London
The Lancet | Year: 2015

In less than 10 years, the prognosis of chronic myeloid leukaemia has changed from that of a fatal disease to a disorder amenable simply to lifelong oral medication and compatible with a normal lifespan. This change has been made possible by a deep understanding of the molecular pathogenesis and a determination to develop targeted and selective drugs. This Seminar summarises the presentation, pathophysiology, diagnosis and monitoring technology, treatment options, side-effects, and outcomes of chronic myeloid leukaemia, and discusses the possibility of cure - ie, stable undetectable or low level disease in the absence of medication. Chronic myeloid leukaemia continues to instruct us in the mechanisms of leukaemogenesis and provides hope not only for similar developments in management of other malignancies, but also for the remarkable speed with which these can move from bench to bedside. Source

Wedzicha J.A.,Imperial College London
Annals of the American Thoracic Society | Year: 2015

Chronic obstructive pulmonary disease (COPD) exacerbations are important events that contribute to worsening health status, disease progression, and mortality. They are mainly triggered by respiratory viruses (especially rhinovirus, the cause of the common cold), but airway bacteria are also involved in their pathogenesis. Exacerbations are associated with both airway and systemic inflammation and, this is mainly neutrophilic in origin. Some patients are especially prone to develop exacerbations, and these have been identified as a high-risk group with increased airway inflammation and greater disease progression. Management of acute exacerbations involves therapy with oral corticosteroids and/or antibiotics, and new therapies are needed. A number of interventions may prevent exacerbations, including vaccination, long-acting bronchodilators, antiinflammatory agents, and long-term antibiotic therapy. Understanding of the pathophysiological mechanisms of COPD exacerbations is important to develop novel therapies. © 2015 by the American Thoracic Society. Source

Barnes P.J.,Imperial College London
Journal of Allergy and Clinical Immunology | Year: 2012

Effective treatment of severe asthma is a major unmet need because patients' symptoms are not controlled on maximum treatment with inhaled therapy. Asthma symptoms can be poorly controlled because of poor adherence to controller therapy, and this might be addressed by using combination inhalers that contain a corticosteroid and long-acting β 2-agonist as reliever therapy in addition to maintenance treatment. New bronchodilators with a longer duration of action are in development, and recent studies have demonstrated the benefit of a long-acting anticholinergic bronchodilator in addition to β 2-agonists in patients with severe asthma. Anti-IgE therapy is beneficial in selected patients with severe asthma. Several new blockers of specific mediators, including prostaglandin D 2, IL-5, IL-9, and IL-13, are also in clinical trials and might benefit patients with subtypes of severe asthma. Several broad-spectrum anti-inflammatory therapies that target neutrophilic inflammation are in clinical development for the treatment of severe asthma, but adverse effects after oral administration might necessitate inhaled delivery. Macrolides might benefit some patients with infection by atypical bacteria, but recent results are not encouraging, although there could be an effect in patients with predominant neutrophilic asthma. Corticosteroid resistance is a major problem in patients with severe asthma, and several molecular mechanisms have been described that might lead to novel therapeutic approaches, including drugs that could reverse this resistance, such as theophylline and nortriptyline. In selected patients with severe asthma, bronchial thermoplasty might be beneficial, but thus far, clinical studies have not been encouraging. Finally, several subtypes of severe asthma are now recognized, and in the future, it will be necessary to find biomarkers that predict responses to specific forms of therapy. © 2011 American Academy of Allergy, Asthma & Immunology. Source

Usmani O.S.,Imperial College London
Allergy, Asthma and Immunology Research | Year: 2014

The small airways have been neglected for many years, but interest in the topic has been rekindled with recent advances in measurement techniques to assess this region and also the ability to deliver therapeutics to the distal airways. Current levels of disease control in asthmatic patients remain poor and there are several contributory factors including; poor treatment compliance, heterogeneity of asthma phenotypes and associated comorbidities. However, the proposition that we may not be targeting all the inflammation that is present throughout the whole respiratory tree may also be an important factor. Indeed decades ago, pathologists and physiologists clearly identified the importance of small airways dysfunction in asthmatic patients. With improved inhaler technology to deliver drug to target the whole respiratory tree and more sensitive measures to assess the distal airways, we should certainly give greater consideration to treating the small airway region when seeing our asthmatic patients in clinic. The aim of this review is to address the relevance of small airways dysfunction in the daily clinical management of patients with asthma. In particular the role of small particle aerosols in the management of patients with asthma will be explored. © 2014 The Korean Academy of Asthma, Allergy and Clinical Immunology. The Korean Academy of Pediatric Allergy and Respiratory Disease. Source

Koppelaar R.H.E.M.,Imperial College London | Weikard H.P.,Wageningen University
Global Environmental Change | Year: 2013

We analyze global elemental phosphorus flows in 2009 for (1) mining to products, (2) animal and human manure flows, (3) crop harvests and animal production, (4) food production, (5) soil erosion, (6) and crop uptake. Informed by the flow assessment the potential and cost of phosphorus usage reduction and recycling measures are quantified, and fed into a constructed phosphorus supply-demand model with reserve assessment to assess the impact of these measures on phosphate rock resource availability. According to our results in 2009 globally 21.4. Mt elemental phosphorus from rock phosphate was consumed in products of which 17.6. Mt used as fertilizers, fully able to cover erosion losses and outputs in agriculture in aggregate, but insufficient from the perspective of bio-available phosphorus in soils. We find substantial scope for phosphorus use reduction, at potentially 6.9. Mt phosphorus, or 32% of 2009 phosphate rock supply. Another 6.1. Mt, or 28% can technologically be recycled from waterways and wastewater, but at a cost substantially above any foreseeable phosphate rock fertilizer price. The model results suggests phosphate rock reserves are sufficient to meet demand into the 22nd century, and can be extended well into the 23rd century with assessed use reduction and recycling measures. © 2013 Elsevier Ltd. Source

Ulug P.,Imperial College London
Cochrane database of systematic reviews (Online) | Year: 2012

Aortic dissection is a potentially life-threatening condition that occurs when a tear forms in the inner lining of the aorta. It has traditionally been treated by blood pressure control (medical treatment) or open surgery, both with high mortality rates. More recently stent-graft repair has been suggested as an alternative. To identify the best management for uncomplicated (without rupture of the organs or malperfusion of the extremities) subacute or chronic type B aortic dissection. The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched their Specialised Register (last searched May 2012) and CENTRAL (2012, Issue 4). Clinical trials databases were searched for ongoing or unpublished studies. All randomised controlled trials designed to compare the outcome of uncomplicated (without rupture of the organs or malperfusion of the extremities) chronic (occurring more than two weeks previously) type B aortic dissection when treated by stenting adjunctive to best medical treatment versus best medical treatment alone were included. Data on all cause and aorta-related mortality at two years was collected and analysed. In addition, secondary outcome measures were analysed, including morbidity, complications (additional endovascular or open surgery for rupture, expansion or malperfusion) and quality of life. A single trial was identified that fulfilled the inclusion criteria (INSTEAD trial). The two-year all cause survival was not statistically significantly different between study groups (95.6% ± 2.5% in the optimised medical therapy (OMT) group and 88.9% ± 3.7% in the thoracic endovascular aneurysm repair (TEVAR) + OMT group; log rank test P = 0.15). Overall, the data at two years were insufficient to make any practice recommendations. However, the data on the anatomic remodeling of dissected aortas observed after TEVAR + OMT is encouraging and future studies should follow up cases for at least five years to see if early endovascular interventions, even in stable initially uncomplicated type B patients, are of long-term benefit. Source

Ng G.,Imperial College London
Cochrane database of systematic reviews (Online) | Year: 2012

Chronic lung disease (CLD) occurs frequently in preterm infants. Bronchodilators have the potential effect of dilating small airways with muscle hypertrophy. Increase in compliance and tidal volume and decrease in pulmonary resistance have been documented with use of bronchodilators in studies of pulmonary mechanics in infants with CLD. Therefore, it is possible that bronchodilators might have a role in the prevention and treatment of CLD. To determine the effect of bronchodilators given either prophylactically or as treatment for CLD on mortality and other complications of prematurity in preterm infants at risk for or having CLD. For this update of the review, searches of The Cochrane Library, Issue 3, 2012; MEDLINE 1966; EMBASE; CINAHL; personal files and reference lists of identified trials were performed in March 2012. In addition Web of Science and abstracts from the Annual meetings of the Pediatric Academic Societies were searched electronically from 2000 to 2012 on PAS Abstracts2view(TM.) No language restrictions were applied. Randomised controlled trials involving preterm infants were eligible for inclusion. Initiation of bronchodilator therapy had to occur within two weeks of birth for prevention of CLD. For treatment of CLD, treatment had to be initiated before discharge from the neonatal unit. The intervention had to include the administration of a bronchodilator either by nebulisation, metered dose inhaler (with or without a spacer device), intravenously or orally versus placebo or no intervention. Eligible studies had to include at least one of the predefined clinical outcomes (mortality, CLD, number of days on oxygen, number of days on ventilator, patent ductus arteriosus (PDA), pulmonary interstitial emphysema (PIE), pneumothorax, any grade of intraventricular haemorrhage (IVH), necrotising enterocolitis (NEC), sepsis and adverse effects of bronchodilators. Adverse effects of bronchodilators included hypokalaemia, tachycardia, cardiac arrhythmias, tremor, hypertension and hyperglycaemia). We used the standard method described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). Two investigators extracted and assessed all data for each study. We reported risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CI) for dichotomous outcomes and weighted mean difference (WMD) for continuous data. In this update we identified four randomised controlled trials investigating the effects of bronchodilators in preterm infants. None of these studies fulfilled our inclusion criterion that clinical outcomes should be reported. One eligible study was previously found dealing with prevention of CLD; this study used salbutamol and enrolled 173 infants. No eligible studies were found dealing with treatment of CLD. Prophylaxis with salbutamol did not show a statistically significant difference in mortality (RR 1.08; 95% CI 0.50 to 2.31; RD 0.01; 95% CI -0.09 to 0.11) or CLD (RR 1.03; 95% CI 0.78 to 1.37; RD 0.02; 95% CI -0.13 to 0.17). No statistically significant differences were seen in other complications associated with CLD or preterm birth. No side effects due to salbutamol were commented on in this study. There are insufficient data to reliably assess the use of salbutamol for the prevention of CLD. Further clinical trials are necessary to assess the role of salbutamol or other bronchodilator agents in prophylaxis or treatment of CLD. Researchers studying the effects of bronchodilators in preterm infants should include relevant clinical outcomes in addition to pulmonary mechanical outcomes. Source

Marin D.,Imperial College London
Hematology / the Education Program of the American Society of Hematology. American Society of Hematology. Education Program | Year: 2012

Imatinib has been the preferred initial therapy for newly diagnosed chronic myeloid leukemia patients for the past 10 years. Recently, other, possibly better, tyrosine kinase inhibitors have been licensed for first-line use based on the early results of 2 large, randomized clinical trials. The pros and cons of the various alternatives to imatinib are analyzed herein, and I try to answer the question of are we ready to abandon imatinib and, if yes, then what treatment should a patient diagnosed today receive. Source

Wang Y.,Imperial College London
Geophysical Journal International | Year: 2011

Seismic anisotropy is evidenced in the inner core, upper mantle and the lower crust in large scale, and the evidence is generally provided by shear wave splitting analysis. Here this paper searches for the evidence of anisotropy in the uppermost crust, by using P-wave arrival times from crosshole seismic measurement to directly estimate velocity anisotropy associated with the fine-layering effect of multiple sedimentary beds. Conceptually fine layering causes the so-called VTI (vertical transverse isotropy) anisotropy with a vertical symmetry and the effect is parametrized by the horizontal and vertical velocity ratio. It is found however that the VTI anisotropic parameter does not have a simple vertical symmetry but is also azimuth dependent. This azimuthal anisotropy may reflect the fracture orientation due to large-scale tectonic movements, and is very important in the production of oil reservoirs, as the seismically fast directions can indicate preferred directions of fluid flow. This paper presents innovative methods for anisotropy analysis in both vertical and horizontal plane. Integrated seismic anisotropy interpretation clearly indicates distinguished strain orientations forming fractures in Oligocenic, Miocenic and Pliocenic sediment, in the edge of the extensional basin immediately next to Tan-Lu Fault, an active continental strike-slip fault zone. © 2011 The Author Geophysical Journal International © 2011 RAS. Source

Three-dimensional seismic reflection data are used to investigate the geometry, scale, and distribution of structures within large clasts (megaclasts) contained within a Tertiary mass transport deposit, Santos Basin, offshore Brazil. Normal faults and folds are observed within the megaclasts; the folds are typically best developed toward either the frontal or lateral margins of the clasts. The highly variable map-view orientation of these structures, their relative ages, and their relationship to the geometry of the basal shear surface indicate that the structures developed during both the motion and arrest of the parent flow. This study indicates that megaclasts may be deformed despite the associated flow being cohesive and lacking turbulence. Deformation is related to local differential shear within the viscous body of the flow and mechanical interaction of megaclasts with the basal shear surface. © 2011 Geological Society of America. Source

Martins Z.,Imperial College London
Elements | Year: 2011

The early Solar System contained a wide range of abiotic organic compounds. As the Solar System evolved, these organic molecules were incorporated into planetesimals and eventually planetary bodies, such as the parent bodies of meteorites. One particular class of meteorites, the carbonaceous meteorites, contains a large variety of extraterrestrial organic compounds. These compounds represent a record of the chemical reactions and conditions in the early Solar System. Different formation mechanisms and sources (interstellar, nebular or parent body) contributed to the inventory of meteoritic organic molecules. Their subsequent delivery to the early Earth may have contributed the first prebiotic building blocks of life. Source

Voulvoulis N.,Imperial College London
Journal of Renewable and Sustainable Energy | Year: 2012

In the face of climate change threatening to cause major alterations to hydrological cycles and taking into account the relationship between water, energy use, and food production, water management challenges today prove more complex than ever to address. This paper, recognising the progress made through science and engineering in the last century, reflects on the need to manage water resources more sustainably. It proposes that a change in mindsets is required in order to reconsider our approach in applying established solutions and utilising current technologies and tools to deliver them, with a renewed focus on re-assessing what the real problems are from a systems perspective. Focusing on the water-energy-food nexus, water reuse using desalination processes as a management option is revisited. Findings demonstrate that interdisciplinary, integrated and holistic solutions have the potential to deliver benefits across different sectors, disciplines, and systems, with a real potential for taking us a bit closer to sustainability. © 2012 American Institute of Physics. Source

Sawmynaden P.,Imperial College London
Cochrane database of systematic reviews (Online) | Year: 2012

Email is a popular and commonly used method of communication, but its use in health care is not routine. Its application in health care has included the provision of information on disease prevention and health promotion, but the effects of using email in this way are not known. This review assesses the use of email for the provision of information on disease prevention and health promotion. To assess the effects of email for the provision of information on disease prevention and health promotion, compared to standard mail or usual care, on outcomes for healthcare professionals, patients and caregivers, and health services, including harms. We searched: the Cochrane Consumers and Communication Review Group Specialised Register (January 2010), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1 2010), MEDLINE (1950 to January 2010), EMBASE (1980 to January 2010), CINAHL (1982 to February 2010), ERIC (1965 to January 2010) and PsycINFO (1967 to January 2010). We searched grey literature: theses/dissertation repositories, trials registers and Google Scholar (searched July 2010). We used additional search methods: examining reference lists, contacting authors. Randomised controlled trials, quasi-randomised trials, controlled before and after studies and interrupted time series studies examining interventions where email is used by healthcare professionals to provide information to patients on disease prevention and health promotion, and taking the form of 1) unsecured email 2) secure email or 3) web messaging. We considered healthcare professionals or associated administrative staff as participants originating the email communication, and patients and caregivers as participants receiving the email communication, in all settings. Email communication was one-way from healthcare professionals or associated administrative staff originating the email communication, to patients or caregivers receiving the email communication. Two authors independently assessed the risk of bias of included studies and extracted data. We contacted study authors for additional information. We assessed risk of bias according to the Cochrane Handbook for Systematic Reviews of Interventions. For continuous outcome measures, we report effect sizes as mean differences (MDs). For dichotomous outcome measures, we report effect sizes as odds ratios (ORs). We conducted a meta-analysis for one primary health service outcome, comparing email communication to standard mail, and report this result as an OR. We included six randomised controlled trials involving 8372 people. All trials were judged to be at high risk of bias for at least one domain. Four trials compared email communication to standard mail and two compared email communication to usual care. For the primary health service outcome of uptake of preventive screening, there was no difference between email and standard mail (OR 0.93; 95% CI 0.69 to 1.24). For both comparisons (email versus standard mail and email versus usual care) there was no difference between the groups for patient or caregiver understanding and support. Results were inconclusive for patient or caregiver behaviours and actions. For email versus usual care only, there was no significant difference between groups for the primary outcome of patient health status and well-being. No data were reported relating to healthcare professionals or harms. The evidence on the use of email for the provision of information on disease prevention and health promotion was weak, and therefore inadequate to inform clinical practice. The available trials mostly provide inconclusive, or no evidence for the outcomes of interest in this review. Future research needs to use high-quality study designs that take advantage of the most recent developments in information technology, with consideration of the complexity of email as an intervention. Source

Pendry J.B.,Imperial College London
New Journal of Physics | Year: 2010

Two parallel dielectric plates separated by vacuum interact through zero-point charge fluctuations and experience friction when the plates are in relative motion and the vacuum is sheared. Even at the absolute zero of temperature, residual quantum fluctuations remain because the zero-point energy gives rise to 'quantum friction'. In a recent paper, the reality of these fluctuations is questioned and the existence of quantum friction is called into question. Here we refute this assertion. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Source

Crowdy D.,Imperial College London
Physics of Fluids | Year: 2010

An analytical formula for the frictional slip length associated with transverse shear flow over a bubble mattress comprising a dilute periodic array of parallel circular-arc grooves protruding into the fluid has recently been presented by Davis and Lauga [Phys. Fluids21, 011701 (2009)]. This letter derives an analytical formula for the slip length associated with longitudinal shear flow over the same surface. The formula is in excellent agreement with a phenomenological result based on finite element simulations given by Teo and Khoo [Microfluid. Nanofluid.9, 499 (2010)]. © 2010 American Institute of Physics. Source

Amis A.A.,Imperial College London
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2012

This paper reviews the functional anatomy of the anterior cruciate ligament (ACL), which has a parallel array of collagen fascicles that have usually been divided into two 'fibre bundles': anteromedial (AM) and posterolateral (PL), according to their tibial attachment sites. The PL bundle has shorter fibres, and so it is subjected to greater tensile strains than the AM bundle when the whole ACL is stretched; its oblique orientation in the coronal plane imbues it with greater ability to resist tibial rotation than the more vertical AM fibre bundle. Most studies have found that the AM bundle is close to isometric when the knee flexes, while the PL bundle slackens approximately 6 mm. There is little evidence of significant fibre bundle elongation in response to tibial rotation. Selective bundle cutting studies have been performed, allowing both the bundle tensions and their contributions to resisting tibial anterior translation and tibial rotation to be calculated. These show that the function of the PL bundle was dominant near knee extension in some studies, particularly when resisting anterior drawer and that its contribution reduced rapidly with knee flexion through 30 degrees. There has been little study of the contributions of the fibre bundles in control of tibial internal-external rotation or the pivot shift: one study found that the AM bundle had larger tensions than the PL bundle during a simulated pivot shift, but another study found that cutting the PL bundle allowed a larger increase in coupled tibial anterior translation than cutting the AM bundle. It was concluded that the AM bundle is most important for resisting tibial anterior drawer-the primary function of the ACL-while the PL bundle is tight near knee extension, when it has a role in control of tibial rotational laxity. There is a clear need for further study of dynamic knee instability, to gain better understanding of how best to reconstruct the ACL and associated tissues. © 2012 Springer-Verlag. Source

Buchbinder E.I.,Imperial College London
Journal of High Energy Physics | Year: 2010

We study the relation between vertex operators in AdS 5 × S 5 and classical spinning string solutions. In the limit of large quantum numbers the treatment of vertex operators becomes semiclassical. In this regime, a given vertex operator carrying a certain set of quantum numbers defines a singular solution. We show in a number of examples that this solution coincides with the classical string solution with the same quantum numbers but written in a different two-dimensional coordinate system. The marginality condition imposed on an operator yields a relation between the energy and the other quantum numbers which is shown to coincide with that of the corresponding classical string solution. We also argue that in some cases vertex operators in AdS 5×S 5 cannot be given by expressions similar to the ones in flat space and a more involved consideration is required. © SISSA 2010. Source

Taylor G.P.,Imperial College London
HIV medicine | Year: 2012

The overall purpose of these guidelines is to provide guidance on best clinical practice in the treatment and management of human immunodeficiency virus (HIV)-positive pregnant women in the UK. The scope includes guidance on the use of antiretroviral therapy (ART) both to prevent HIV mother-to-child transmission (MTCT) and for the welfare of the mother herself, guidance on mode of delivery and recommendations in specific patient populations where other factors need to be taken into consideration,such as coinfection with other agents. The guidelines are aimed at clinical professionals directly involved with, and responsible for, the care of pregnant women with HIV infection. Source

Naji M.,Maidstone and Tunbridge Wells NHS trust | Al-Nahhas A.,Imperial College London
European Journal of Nuclear Medicine and Molecular Imaging | Year: 2012

Neuroectodermal tumours arise from chromaffin cells and possess the ability to secrete catecholamines. They are generally rare and may occur in association with a variety of hereditary syndromes such as MEN-2A and 2B, neurofibromatosis type 1 and von Hippel-Lindau disease. The most common types are phaeochromocytoma arising from the adrenal medulla and paraganglioma of extra-adrenal origin. Phaeochromocytomas tend to be benign and are often associated with a gene mutation if the disease is bilateral, while paragangliomas are often malignant, have a more aggressive nature and tend to metastasize. There are no specific histological or immunohistochemical features that indicate the malignant potential and the diagnosis of malignancy can only be established by the presence of distant metastases. Therefore, imaging can play a vital role in the diagnosis, localization, staging and assessment of spread. Traditionally, this is achieved with a combination of cross-sectional (CT and MRI) and functional (123I-MIBG or 111In- octreotide) imaging. However, these modalities are not adequate and achieve moderate sensitivity. The introduction of 68Ga-DOTA peptide in PET/CT imaging has led to improved receptor targeting and superb PET resolution, as well as accurate localization of lesions. The use of this technique in neuroectodermal tumours has been shown to be superior to all available modalities, but the available data are limited and larger studies are awaited to establish its role in the management of these tumours. © 2011 Springer-Verlag. Source

Maertens G.N.,Imperial College London
Nucleic Acids Research | Year: 2016

To establish infection, a retrovirus must insert a DNA copy of its RNA genome into host chromatin. This reaction is catalysed by the virally encoded enzyme integrase (IN) and is facilitated by viral genus-specific host factors. Herein, cellular serine/threonine protein phosphatase 2A (PP2A) is identified as a functional IN binding partner exclusive to δ-retroviruses, including human T cell lymphotropic virus type 1 and 2 (HTLV-1 and HTLV-2) and bovine leukaemia virus (BLV). PP2A is a heterotrimer composed of a scaffold, catalytic and one of any of four families of regulatory subunits, and the interaction is specific to the B′ family of the regulatory subunits. B′-PP2A and HTLV-1 IN display nuclear co-localization, and the B′ subunit stimulates concerted strand transfer activity of δ-retroviral INs in vitro. The protein-protein interaction interface maps to a patch of highly conserved residues on B′, which when mutated render B′ incapable of binding to and stimulating HTLV-1 and -2 IN strand transfer activity. © The Author 2015. Published by Oxford University Press on behalf of Nucleic Acids Research. Source

Salhiyyah K.,Imperial College London
Cochrane database of systematic reviews (Online) | Year: 2012

Intermittent claudication (IC) is a symptom of peripheral arterial occlusive disease (PAD). It is associated with high morbidity and mortality. Pentoxifylline is one of many drugs used to treat IC. Pentoxifylline decreases blood viscosity, improves erythrocyte flexibility, and increases microcirculatory flow and tissue oxygen concentration.Many studies have evaluated the efficacy of pentoxifylline in treating PAD but the results of these studies are very variable. To determine the efficacy of pentoxifylline in improving the walking capacity (that is pain-free walking distance and the total (absolute, maximum) walking distance) of patients with stable intermittent claudication, Fontaine stage II. The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched January 2011) and CENTRAL (2011, Issue 1). In addition, we searched MEDLINE (Week 2 January 2011) and EMBASE (2011 Week 03). ClinicalTrials.gov and Current Controlled Trials were searched for ongoing or unpublished trials. All double blind, randomised controlled trials (RCTs) comparing pentoxifylline to placebo or any other pharmacological intervention in patients with IC Fontaine stage II. Included studies were assessed separately by two review authors. Data were matched and disagreements resolved by discussion. The quality of the studies was assessed using the Jadad score and the Cochrane risk of bias tool. Results relating to pain-free walking distance (PFWD) and total walking distance (TWD) were collected. Studies were compared based on the duration and dose of pentoxifylline. Twenty-three studies with 2816 participants were included in this review. There was considerable heterogeneity between the included studies with regards to multiple variables including duration of treatment, dose of pentoxifylline, baseline walking distance and patient characteristics, and therefore pooled analysis was not possible. The quality of the included studies was generally low. There was very large variability in the reported findings between the individual studies. In a total of 17 studies which compared pentoxifylline with placebo, of which 14 reported TWD and 11 reported PFWD, the difference in percentage improvement in TWD for pentoxifylline over placebo ranged from 1.2% to 155.9%, and for PFWD the difference ranged from -33.8% to 73.9%. Testing for statistical significance of these results was generally not possible due to the lack of data. There was no statistically significant difference in ankle brachial pressure index (ABI) between the pentoxifylline and placebo groups. Pentoxifylline was generally well tolerated. Given the generally poor quality of the published studies and the large degree of heterogeneity in the interventions and the results, the overall benefit of pentoxifylline for patients with Fontaine class II intermittent claudication remains uncertain. Pentoxifylline is generally well tolerated.  Based on the totality of the available evidence, it is possible that pentoxifylline could have a place in the treatment of IC as a means of improving walking distance and as a complimentary treatment assuming all other essential measures such as lifestyle change, exercise and treatment for secondary prevention have been taken into account. However, the response to pentoxifylline should be assessed on an individual basis. Source

Car J.,Imperial College London
Cochrane database of systematic reviews (Online) | Year: 2012

Missed appointments are a major cause of inefficiency in healthcare delivery, with substantial monetary costs for the health system, leading to delays in diagnosis and appropriate treatment. Patients' forgetfulness is one of the main reasons for missed appointments, and reminders may help alleviate this problem. Modes of communicating reminders for appointments to patients include face-to-face communication, postal messages, calls to landlines or mobile phones, and mobile phone messaging. Mobile phone messaging applications such as Short Message Service (SMS) and Multimedia Message Service (MMS) could provide an important, inexpensive delivery medium for reminders for healthcare appointments. To assess the effects of mobile phone messaging reminders for attendance at healthcare appointments. Secondary objectives include assessment of patients' and healthcare providers' evaluation of the intervention; costs; and possible risks and harms associated with the intervention. We searched the Cochrane Central Register of Controlled Trials (CENTRAL,The Cochrane Library 2009, Issue 2), MEDLINE (OvidSP) (January 1993 to June 2009), EMBASE (OvidSP) (January 1993 to June 2009), PsycINFO (OvidSP) (January 1993 to June 2009), CINAHL (EbscoHOST) (January 1993 to June 2009), LILACS (January 1993 to June 2009) and African Health Anthology (January 1993 to June 2009). We also reviewed grey literature (including trial registers) and reference lists of articles. We included randomised controlled trials (RCTs), quasi-randomised controlled trials (QRCTs), controlled before-after (CBA) studies, or interrupted time series (ITS) studies with at least three time points before and after the intervention. We included studies assessing mobile phone messaging as reminders for healthcare appointments. We only included studies in which it was possible to assess effects of mobile phone messaging independent of other technologies or interventions.   Two review authors independently assessed all studies against the inclusion criteria, with any disagreements resolved by a third review author. Study design features, characteristics of target populations, interventions and controls, and results data were extracted by two review authors and confirmed by a third author. Primary outcomes of interest were rate of attendance at healthcare appointments. We also considered health outcomes as a result of the intervention, patients' and providers' evaluation of the intervention, perceptions of safety, costs, and potential harms or adverse effects. As the intervention characteristics and outcome measures were similar across included studies, we conducted a meta-analysis to estimate an overall effect size. We included four randomised controlled trials involving 3547 participants. Three studies with moderate quality evidence showed that mobile text message reminders improved the rate of attendance at healthcare appointments compared to no reminders (risk ratio (RR) 1.10 (95% confidence interval (CI) 1.03 to 1.17)). One low quality study reported that mobile text message reminders with postal reminders, compared to postal reminders, improved rate of attendance at healthcare appointments (RR 1.10 (95% CI 1.02 to 1.19)). However, two studies with moderate quality of evidence showed that mobile phone text message reminders and phone call reminders had a similar impact on healthcare attendance (RR 0.99 (95% CI 0.95 to 1.03). The costs per attendance of mobile phone text message reminders were shown to be lower compared to phone call reminders. None of the included studies reported outcomes related to harms or adverse effects of the intervention, nor health outcomes or user perception of safety related to the intervention. There is moderate quality evidence that mobile phone text message reminders are more effective than no reminders, and low quality evidence that text message reminders with postal reminders are more effective than postal reminders alone. Further, according to the moderate quality evidence we found, mobile phone text message reminders are as effective as phone call reminders. Overall, there is limited evidence on the effects of mobile phone text message reminders for appointment attendance, and further high-quality research is required to draw more robust conclusions. Source

Hallsworth M.,Imperial College London
Oxford Review of Economic Policy | Year: 2014

Governments have become increasingly interested in the 'explosion' of research into taxpayer behaviour. This article briefly reviews two main theories of tax compliance ('deterrence' and 'non-deterrence'), before discussing the recent rapid rise of natural field experiments (NFEs) in this area. These NFEs represent a 'win-win' for policy-makers and academics, since they can test theories while also evaluating the impact of a specific intervention in the real world. The evidence from NFEs shows that deterrence approaches improve compliance, while the case for non-deterrence approaches is less conclusive at the moment. NFEs could be improved by paying more attention to findings from behavioural science that apparently incidental factors, such as timing, framing, and complexity, substantially affect whether compliance occurs or not. New directions for future studies include: network effects, tax payments (in addition to declarations), the behaviour of firms, the provision of public goods, and the relationship between attitudes and behaviour. © The Author 2014. Published by Oxford University Press. Source

Jones M.,Imperial College London
Current Allergy and Asthma Reports | Year: 2015

Laboratory animal workers face a high risk of developing laboratory animal allergy as a consequence of inhaling animal proteins at work; this has serious consequences for their health and future employment. Exposure to animal allergen remains to be the greatest risk factor although the relationship is complex, with attenuation at high allergen exposure. Recent evidence suggests that this may be due to a form of natural immunotolerance. Furthermore, the pattern of exposure to allergen may also be important in determining whether an allergic or a tolerant immune response is initiated. Risk associated with specific tasks in the laboratory need to be determined to provide evidence to devise a code of best practice for working within modern laboratory animal facilities. Recent evidence suggests that members of lipocalin allergens, such as Mus m 1, may act as immunomodulatory proteins, triggering innate immune receptors through toll-like receptors and promoting airway laboratory animal allergy. This highlights the need to understand the relationship between endotoxin, animal allergen and development of laboratory animal allergy to provide a safe working environment for all laboratory animal workers. © 2015, Springer Science+Business Media New York. Source

Shah R.R.,Rashmi Shah Consultancy Ltd | Smith R.L.,Imperial College London
Drug Metabolism and Disposition | Year: 2015

Phenoconversion transiently converts genotypic extensive metabolizers (EMs) into phenotypic poor metabolizers (PMs) of drugs, potentially with corresponding changes in clinical response. This phenomenon, typically resulting from coadministration of medications that inhibit certain drug metabolizing enzymes (DMEs), is especially well documented for enzymes of the cytochrome P450 family. Nonclinical evidence gathered over the last two decades also strongly implicates elevated levels of some proinflammatory cytokines, released during inflammation, in down-regulation of drug metabolism, especially by certain DMEs of the P450 family, thereby potentially causing transient phenoconversion. Clinically, phenoconversion of NAT2, CYP2C19, and CYP2D6 has been documented in inflammatory conditions associated with elevated cytokines, such as human immunodeficiency virus infection, cancer, and liver disease. The potential of other inflammatory conditions to cause phenoconversion has not been studied but experimental and anecdotal clinical evidence supports infectioninduced down-regulation of CYP1A2, CYP3A4, and CYP2C9 as well. Collectively, the evidence supports a hypothesis that certain inflammatory conditions associated with elevated proinflammatory cytokines may cause phenoconversion of certain DMEs. Since inflammatory conditions associated with elevated levels of proinflammatory cytokines are highly prevalent, phenoconversion of genotypic EM patients into transient phenotypic PMs may be more frequent than appreciated. Since drug pharmacokinetics, and therefore the clinical response, is influenced by DME phenotype rather than genotype per se, phenoconversion (whatever its cause) can have a significant impact on the analysis and interpretation of genotype-focused clinical outcome association studies. There is a risk that focusing on genotype alone may miss important associations between clinical outcomes and DME phenotypes, thus compromising future prospects of personalized medicine. © 2015 by The American Society for Pharmacology and Experimental Therapeutics. Source

Cantilever arrays have been used to monitor biochemical interactions and their associated stress. However, it is often necessary to passivate the underside of the cantilever to prevent unwanted ligand adsorption, and this process requires tedious optimization. Here, we show a way to immobilize membrane receptors on nanomechanical cantilevers so that they can function without passivating the underlying surface. Using equilibrium theory, we quantitatively describe the mechanical responses of vancomycin, human immunodeficiency virus type 1 antigens and coagulation factor VIII captured on the cantilever in the presence of competing stresses from the top and bottom cantilever surfaces. We show that the area per receptor molecule on the cantilever surface influences ligand–receptor binding and plays an important role on stress. Our results offer a new way to sense biomolecules and will aid in the creation of ultrasensitive biosensors. © 2015 Nature Publishing Group Source

Bearman P.W.,Imperial College London
Journal of Fluids and Structures | Year: 2011

This paper presents a selective review of recent research on vortex-induced vibrations of isolated circular cylinders and the flow and vibration of circular cylinders in a tandem arrangement; a common thread being that the topics raised are of particular interest to the author. The influence of Reynolds number on the response of isolated cylinders is presented and recent developments using forced vibration are discussed. The response of a cylinder free to respond in the in-line and transverse directions is contrasted with that of a cylinder responding in only one direction. The interference between two circular cylinders is discussed and prominence given to the case of cylinders in a tandem arrangement. The origin of the time-mean lift force on the downstream cylinder is considered together with the cause of the large amplitude transverse vibration experienced by the cylinder above vortex resonance. This wake-induced vibration is shown to be a form of vortex-induced vibration. © 2011 Elsevier Ltd. Source

Cardona G.A.,Livestock Laboratory | Carmena D.,Imperial College London
Veterinary Parasitology | Year: 2013

Cystic echinococcosis (CE) is an important and widespread zoonotic infection caused by the larval stages of taeniid cestodes of the genus Echinococcus. The disease represents a serious animal health concern in many rural areas of the world, causing important economic losses derived from decreased productivity and viscera condemnation in livestock species. In this review we aim to provide a comprehensive overview on recent research progress in the epidemiology of CE in production animals from a global perspective. Particular attention has been paid to the discussion of the extent and significance of recent molecular epidemiologic data. The financial burden associated to CE on the livestock industry has also been addressed. Data presented are expected to improve our current understanding of the parasite's geographical distribution, transmission, host range, immunogenicity, pathogenesis, and genotype frequencies. This information should be also valuable for the design and implementation of more efficient control strategies against CE. © 2012 Elsevier B.V. Source

Leader E.,Imperial College London | Lorce C.,University Paris - Sud | Lorce C.,University of Liege
Physics Reports | Year: 2014

The general question, crucial to an understanding of the internal structure of the nucleon, of how to split the total angular momentum of a photon or gluon into spin and orbital contributions is one of the most important and interesting challenges faced by gauge theories like Quantum Electrodynamics and Quantum Chromodynamics. This is particularly challenging since all QED textbooks state that such a splitting cannot be done for a photon (and a fortiori for a gluon) in a gauge-invariant way, yet experimentalists around the world are engaged in measuring what they believe is the gluon spin! This question has been a subject of intense debate and controversy, ever since, in 2008, it was claimed that such a gauge-invariant split was, in fact, possible. We explain in what sense this claim is true and how it turns out that one of the main problems is that such a decomposition is not unique and therefore raises the question of what is the most natural or physical choice. The essential requirement of measurability does not solve the ambiguities and leads us to the conclusion that the choice of a particular decomposition is essentially a matter of taste and convenience. In this review, we provide a pedagogical introduction to the question of angular momentum decomposition in a gauge theory, present the main relevant decompositions and discuss in detail several aspects of the controversies regarding the question of gauge invariance, frame dependence, uniqueness and measurability. We stress the physical implications of the recent developments and collect into a separate section all the sum rules and relations which we think experimentally relevant. We hope that such a review will make the matter amenable to a broader community and will help to clarify the present situation. © 2014 Elsevier B.V. Source

Brazeau M.D.,Imperial College London | Friedman M.,University of Oxford
Nature | Year: 2015

Fossils of early gnathostomes (or jawed vertebrates) have been the focus of study for nearly two centuries. They yield key clues about the evolutionary assembly of the group's common body plan, as well the divergence of the two living gnathostome lineages: the cartilaginous and bony vertebrates. A series of remarkable new palaeontological discoveries, analytical advances and innovative reinterpretations of existing fossil archives have fundamentally altered a decades-old consensus on the relationships of extinct gnathostomes, delivering a new evolutionary framework for exploring major questions that remain unanswered, including the origin of jaws. © 2015 Macmillan Publishers Limited. All rights reserved. Source

Bowcock A.M.,Imperial College London
Thorax | Year: 2014

Lung cancer usually presents as advanced stage disease and there is a need for early diagnosis so that appropriate treatments can be provided prior to tumour progression. Copy number variation is frequently detected in tumours and can contribute to tumour progression. This is because regions harbouring DNA imbalance can contain genes encoding critical proteins whose altered dosage contributes to the neoplastic process. Three copy number variations (CNVs) from chromosomes 3p26-p11.1 (loss), 3q26.2-29 (gain) and 6q25.3-24.3 (loss) have previously been described in individuals presenting with endobronchial squamous metaplasia. These CNVs were predictors of cancer diagnosed within 44 months with 97% accuracy. An evaluation of this CNV-based classifier with an independent set of 12 samples (10 men and 2 women), each with a carcinoma in situ or invasive carcinoma at the same site at follow-up demonstrated 92% prediction accuracy. The negative predictive value of this classifier was 89%. The gain at 3q26.2-q29 contributed the most to the classification, being present in virtually all lesions. This region harbours the PIK3CA gene and evaluation of the number of copies of this gene gave very similar results to those from array comparative genomic hybridisation. This type of test can be performed on sputum or bronchial brushings. Larger cohorts now need to be examined to confirm this finding and to possibly refine the regions of CNV. This type of approach paves the way for future molecular analyses to assist in selecting subjects with endobronchial squamous metaplastic or dysplastic lesions who might benefit from more aggressive therapeutic intervention or surveillance. Source

Muxworthy A.R.,Imperial College London
Physics of the Earth and Planetary Interiors | Year: 2010

The use of a domain-state independent method (the Wilson method) of acquiring absolute palaeointensities is tested using three sets of historical lavas from Mexico, Italy and Iceland. The Wilson method works by plotting continuous thermal demagnetisation curve data for the original natural remanent magnetisation against those for a laboratory-induced thermoremanence. By comparing the predicted intensities with the known fields, a new empirically derived rejection criterion is proposed that accounts for chemical alteration and improves the accuracy of the palaeointensity estimates. The Wilson palaeointensity estimates are compared with palaeointensity determinations made on sister samples using standard Thellier-type heating. Generally, the Wilson palaeointensity estimates compare favourably for samples that yielded technically correct Thellier-type determinations. However, at one locality the Wilson method did not yield any estimates due to severe chemical alteration, in contrast it was still possible to determine palaeointensity estimates from the lower temperature Thellier data. To assess the Wilson palaeointensity protocol's ability to return a correct estimate for a true multidomain system, a synthetic multidomain magnetite sample was imparted with a thermoremanent magnetisation. The Wilson protocol returned the correct palaeointensity within error, in contrast the Thellier-type protocol failed. As the Wilson method is significantly faster than Thellier-type methods, it is suggested that the Wilson method should be tried as a 'first-approach' in palaeointensity studies, or for samples dominated by multidomain material. © 2010 Elsevier B.V. All rights reserved. Source

Muller E.A.,Imperial College London | Mejia A.,University of Concepcion
Journal of Physical Chemistry Letters | Year: 2014

Literature values regarding the pressure dependence of the interfacial tension of the system of carbon dioxide (CO2) + water (H 2O) show an unexplained divergence and scatter at the transition between low-pressure gas-liquid equilibrium and the high-pressure liquid-liquid equilibrium. We employ the Statistical Associating Fluid Theory (SAFT) and canonical molecular dynamics simulations based on the corresponding coarse grained force field to map out the phase diagram of the mixture and the interfacial tension for this system. We showcase how at ambient temperatures a triple point (gas-liquid-liquid) is expected and detail the implications that the appearance of the third phase has on the interfacial tensions of the system. © 2014 American Chemical Society. Source

Whittaker A.C.,Imperial College London | Boulton S.J.,University of Plymouth
Journal of Geophysical Research: Earth Surface | Year: 2012

The rate at which transient knickpoints propagate through a landscape fundamentally controls the rate of geomorphic response to tectonic and climatic perturbation. Here we present knickpoint retreat rates upstream of active faults for 19 bedrock catchments in Turkey and 11 bedrock catchments in Italy where we have very good constraints on both the magnitude and timing of the tectonic perturbation and where climate histories are well documented. We show that the knickpoints have average retreat rates of between 0.2 and 2 mm/yr for catchments with drainage areas between 6 and 65 km2 and we test whether differences in rock mass strength and catchment size are sufficient to explain this range in retreat rates. Our analysis suggests that even accounting for these two variables, knickpoint propagation velocities differ markedly, and we show that channels crossing faults with higher throw rates have knickpoints that are retreating faster. The dependence of knickpoint retreat velocity on throw rate is at least as important as catchment drainage area. These results indicate, counterintuitively, that landscapes forced by large amplitude tectonic perturbations will have shorter response times than those perturbed by smaller amplitude changes. The link between the knickpoint propagation velocity and throw rate is largely (but not completely) explained by channel narrowing in areas of high uplift rate. Channel steepening upstream of the active faults may explain all of the residual dependency of knickpoint retreat rate on fault throw rate, but only if the slope exponent, n, in the standard stream power model is greater than 1.3. However, we cannot rule out a role for sediment supply in driving enhanced knickpoint retreat rate in addition to the well-documented channel narrowing effect. Finally, we find that mean knickpoints retreat rates in Turkey are only half of those in Italy, for catchments of equivalent size, crossing faults with similar throw rates. This difference in fluvial response time is accounted for by long-term differences in the ratio of precipitation to infiltration in the two areas over the last 1 My. © Copyright 2012 by the American Geophysical Union. Source

Three-dimensional seismic-reflection data are used to characterize the seismic expression and investigate the origin of two mass transport complexes (sensu Moscardelli and Wood, 2007) that are contained in two saltrelated minibasins on the São Paulo Plateau, offshore SE Brazil. The mass transport complexes contain numerous slide blocks, which are expressed on seismic data as broadly tabular packages of weakly deformed reflections. Individual slide blocks are up to 50 m thick and up to 1 km2 in plan view. The slide blocks are flanked by laterally continuous reflections, which are interpreted as the seismic expression of either a thin mudstonedominated debrite deposit or a thin interval of hemi pelagic mudstones. The surface that bounds the base of the two mass transport complexes is planar, and this suggests that the associated gravity-flow event caused only limited erosion of the seafloor. The upper surfaces of the mass transport complexes are very rugose and onlapped by overlying strata, indi cating that the slide blocks formed seabed relief of up to 20 m. The complexes occur at the base of a unit that thins toward the margins of the studied minibasins, and the slide blocks in the mass transport complexes decrease in size and density away from the saltcored structural high that separates the two minibasins. Based on its seismic stratigraphic context and the spatial distribution of the slide blocks that they contain, the mass transport complexes are interpreted to have been derived from the failure of the margins of the salt-cored high in response to a period of relatively rapid minibasin sub sidence. The results of this study indicate that large volumes of sedimentary material may be derived from the margins of salt-related minibasins in relatively distal submarine settings. From a geohazard perspective, this observa tion is important because the risk asso ciated with submarine slope failure, and the transport and emplacement of large blocks, is typically thought to be low in relatively distal, deepwater environments. © 2012 Geological Society of America. Source

Selley R.C.,Imperial College London
Marine and Petroleum Geology | Year: 2012

The UK's first well to encounter shale gas was drilled into the Upper Jurassic Kimmeridge Clay in 1875, but its significance was not realised at the time. 25 years ago research at Imperial College applied the US shale gas paradigm to evaluate the UK's shale gas potential. Shale sequences with potential for gas production were identified in Carboniferous strata in the Midlands, and in Jurassic strata, particularly in the Weald. Without encouragement from Her Majesty's Government no exploration resulted from this initial research. Publication of the results of the project was rejected by many UK journals. It was finally published in the USA in 1987. Subsequent evaluations of UK petroleum resources by the Department of Energy and its descendants published in 2001 and 2003 omitted any mention of shale gas resources. Recent timely re-evaluations of the UK's shale gas potential have been carried out by the British Geological Survey and the Department for Energy & Climate Change. In 2008 the 13th Round of Onshore Licensing resulted in the award of several blocks for shale gas exploration, though bids were often based on a quest for both shale gas and conventional prospects. Cuadrilla Resource's Preese Hall No. 1 well drilled in 2010 was the first well drilled to specifically test for UK shale gas. The same drilling and fracturing techniques that led to the shale gas renaissance in the USA are now being applied to extracting oil from organic-rich shales that are currently in the oil window. It is interesting to speculate that oil may be produced by such techniques from the thermally mature Jurassic shales in the Wessex and Weald basins in the southern UK. © 2011 Elsevier Ltd. Source

Ivanov M.,Imperial College London | Ivanov M.,Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy | Smirnova O.,Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy
Physical Review Letters | Year: 2011

An attosecond streak camera holds the promise of time resolving the dynamics of photoionization with a few-attosecond accuracy. But can the attosecond measurement be disentangled from the process it measures? We address this question by deriving simple closed-form analytical expressions for the measurement-related apparent time delays in photoionization, associated with the application of the attosecond streak camera and/or resolution of attosecond beating by interference of two-photon transitions techniques. Our analytical results are accurate on about the 1 asec level and show that both intrinsic and measurement-induced delays depend on the same scattering phase and are, therefore, not independent. We also suggest a procedure for extracting intrinsic time delays from the measurement and a possible resolution of the controversy caused by the experiments of Schultze et al.. © 2011 American Physical Society. Source

Tachibana Y.,RMIT University | Tachibana Y.,Japan Science and Technology Agency | Tachibana Y.,Osaka University | Vayssieres L.,Xian Jiaotong University | Durrant J.R.,Imperial College London
Nature Photonics | Year: 2012

Hydrogen generated from solar-driven water-splitting has the potential to be a clean, sustainable and abundant energy source. Inspired by natural photosynthesis, artificial solar water-splitting devices are now being designed and tested. Recent developments based on molecular and/or nanostructure designs have led to advances in our understanding of light-induced charge separation and subsequent catalytic water oxidation and reduction reactions. Here we review some of the recent progress towards developing artificial photosynthetic devices, together with their analogies to biological photosynthesis, including technologies that focus on the development of visible-light active hetero-nanostructures and require an understanding of the underlying interfacial carrier dynamics. Finally, we propose a vision for a future sustainable hydrogen fuel community based on artificial photosynthesis. © 2012 Macmillan Publishers Limited. All rights reserved. Source