235 research outputs found

    Taming tosyl azide: the development of a scalable continuous diazo transfer process

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    Heat and shock sensitive tosyl azide was generated and used on demand in a telescoped diazo transfer process. Small quantities of tosyl azide were accessed in a one pot batch procedure using shelf stable, readily available reagents. For large scale diazo transfer reactions tosyl azide was generated and used in a telescoped flow process, to mitigate the risks associated with handling potentially explosive reagents on scale. The in situ formed tosyl azide was used to rapidly perform diazo transfer to a range of acceptors, including β-ketoesters, β-ketoamides, malonate esters and β-ketosulfones. An effective in-line quench of sulfonyl azides was also developed, whereby a sacrificial acceptor molecule ensured complete consumption of any residual hazardous diazo transfer reagent. The telescoped diazo transfer process with in-line quenching was used to safely prepare over 21 g of an α-diazocarbonyl in >98% purity without any column chromatography

    Chinese medicine in the West 2009

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    In January 1985 The Journal of Chinese Medicine published an edited transcript of a discussion called ‘Acupuncture in the West’ between Peter Deadman, Ted Kaptchuk, Giovanni Maciocia and Felicity Moir. It was a particularly popular article and to celebrate the 30th anniversary of the JCM we decided to convene another discussion, in London in March 2009. Present this time were Peter Deadman (PD), Hugh MacPherson (HM), Daniel Maxwell (DM), Felicity Moir (FM) and Volker Scheid (VS). All are past or present practitioners of acupuncture and/or herbal medicine

    Notes on the integration of numerical relativity waveforms

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    A primary goal of numerical relativity is to provide estimates of the wave strain, hh, from strong gravitational wave sources, to be used in detector templates. The simulations, however, typically measure waves in terms of the Weyl curvature component, ψ4\psi_4. Assuming Bondi gauge, transforming to the strain hh reduces to integration of ψ4\psi_4 twice in time. Integrations performed in either the time or frequency domain, however, lead to secular non-linear drifts in the resulting strain hh. These non-linear drifts are not explained by the two unknown integration constants which can at most result in linear drifts. We identify a number of fundamental difficulties which can arise from integrating finite length, discretely sampled and noisy data streams. These issues are an artifact of post-processing data. They are independent of the characteristics of the original simulation, such as gauge or numerical method used. We suggest, however, a simple procedure for integrating numerical waveforms in the frequency domain, which is effective at strongly reducing spurious secular non-linear drifts in the resulting strain.Comment: 23 pages, 10 figures, matches final published versio

    Historic Farmsteads: Preliminary Character Statement - North East region

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    This document is one of eight Preliminary Character\ud Statements, which provide information on the\ud characteristics of traditional farm buildings in each\ud Region

    The impact of storage conditions upon gentamicin coated antimicrobial implants

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    A systematic approach was developed to investigate the stability of gentamicin sulfate (GS) and GS/poly (lactic-co-glycolic acid) (PLGA) coatings on hydroxyapatite surfaces. The influence of environmental factors (light, humidity, oxidation and heat) upon degradation of the drug in the coatings was investigated using liquid chromatography with evaporative light scattering detection and mass spectrometry. GS coated rods were found to be stable across the range of environments assessed, with only an oxidizing atmosphere resulting in significant changes to the gentamicin composition. In contrast, rods coated with GS/PLGA were more sensitive to storage conditions with compositional changes being detected after storage at 60 °C, 75% relative humidity or exposure to light. The effect of γ-irradiation on the coated rods was also investigated and found to have no significant effect. Finally, liquid chromatography–mass spectrometry analysis revealed that known gentamines C1, C1a and C2 were the major degradants formed. Forced degradation of gentamicin coatings did not produce any unexpected degradants or impurities

    An axisymmetric evolution code for the Einstein equations on hyperboloidal slices

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    We present the first stable dynamical numerical evolutions of the Einstein equations in terms of a conformally rescaled metric on hyperboloidal hypersurfaces extending to future null infinity. Axisymmetry is imposed in order to reduce the computational cost. The formulation is based on an earlier axisymmetric evolution scheme, adapted to time slices of constant mean curvature. Ideas from a previous study by Moncrief and the author are applied in order to regularize the formally singular evolution equations at future null infinity. Long-term stable and convergent evolutions of Schwarzschild spacetime are obtained, including a gravitational perturbation. The Bondi news function is evaluated at future null infinity.Comment: 21 pages, 4 figures. Minor additions, updated to agree with journal versio

    Clonal structure of Ceratocystis manginecans populations from mango wilt disease in Oman and Pakistan

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    Ceratocystis manginecans has recently been described from Oman and Pakistan where the fungus causes a serious wilt disease of mango. In both countries, the disease has moved rapidly throughout mango producing areas leading to the mortality of thousands of mango trees. The disease is associated with the infestation of the wood-boring beetle Hypocryphalus mangiferae that consistently carries C. manginecans. The aim of this study was to consider the population structure of C. manginecans isolated from Oman and Pakistan using microsatellite markers and amplified fragment length polymorphisms (AFLPs).Population genetic analysis of C. manginecans isolates from diseased mango tissue and bark beetles associated with the disease in Oman and Pakistan, showed no genetic diversity. The apparently clonal nature of the population suggests strongly that C. manginecans was introduced into these countries as a single event or from another clonal source.Tree Protection Co-operative Programme (TPCP), National Research Foundation (NRF), South Africa and the Ministry of Agriculture and Fisheries in Sultanate of Oman.http://link.springer.com/journal/13313hb201

    Mango sudden decline pathogen, Ceratocystis manginecans, is vectored by Hypocryphalus mangiferae (Coleoptera : Scolytinae) in Oman

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    In Oman, the bark beetle Hypocryphalus mangiferae is closely associated with trees affected by mango sudden decline disease caused by Ceratocystis manginecans. Although it has previously been assumed that this beetle plays a role in the dispersal of the pathogen, this has not been established experimentally. The aim of this study was to determine whether H. mangiferae vectors C. manginecans from infected to healthy mango trees. A survey conducted in northern Al Batinah region of Oman revealed that H. mangiferae was closely associated with mango sudden decline disease symptoms and it was found on trees in the early stages of the disease. Healthy, 2- year-old mango seedlings were exposed to H. mangiferae collected from diseased mango trees. Seedlings were infested by the bark beetles and after 6 weeks, typical mango sudden decline disease symptoms were observed. Ceratocystis manginecans was isolated from the wilted mango seedlings while uncolonized control seedlings remained healthy. The results show that H. mangiferae vectors C. manginecans in Oman and is, therefore, an important factor in the epidemiology of this disease.The National Research Foundation (NRF)http://www.springerlink.com /content/100265

    The XMM Cluster Survey: The Stellar Mass Assembly of Fossil Galaxies

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    This paper presents both the result of a search for fossil systems (FSs) within the XMM Cluster Survey and the Sloan Digital Sky Survey and the results of a study of the stellar mass assembly and stellar populations of their fossil galaxies. In total, 17 groups and clusters are identified at z < 0.25 with large magnitude gaps between the first and fourth brightest galaxies. All the information necessary to classify these systems as fossils is provided. For both groups and clusters, the total and fractional luminosity of the brightest galaxy is positively correlated with the magnitude gap. The brightest galaxies in FSs (called fossil galaxies) have stellar populations and star formation histories which are similar to normal brightest cluster galaxies (BCGs). However, at fixed group/cluster mass, the stellar masses of the fossil galaxies are larger compared to normal BCGs, a fact that holds true over a wide range of group/cluster masses. Moreover, the fossil galaxies are found to contain a significant fraction of the total optical luminosity of the group/cluster within 0.5R200, as much as 85%, compared to the non-fossils, which can have as little as 10%. Our results suggest that FSs formed early and in the highest density regions of the universe and that fossil galaxies represent the end products of galaxy mergers in groups and clusters. The online FS catalog can be found at http://www.astro.ljmu.ac.uk/~xcs/Harrison2012/XCSFSCat.html.Comment: 30 pages, 50 figures. ApJ published version, online FS catalog added: http://www.astro.ljmu.ac.uk/~xcs/Harrison2012/XCSFSCat.htm
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