249 research outputs found

    On-POM Ring-Opening Polymerisation of N-Carboxyanhydrides

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    The ring-opening polymerisation of a-amino acid N-carboxyanhydrides (NCAs) offers a simple and scalable route to polypeptides with predicted and narrow molecular weight distributions. Here we show how polyoxometalates (POMs)-redox-active molecular metal-oxide anions-can serve as inorganic scaffold initiators for such NCA polymerisations. This "On-POM polymerisation" strategy serves as an innovative platform to design hybrid materials with additive or synergistic properties stemming from the inorganic and polypeptide component parts. We have used this synthetic approach to synthesise a library of bactericidal poly(lysine)-POM hybrid derivatives that can be used to prevent biofilm formation. This versatile "On-POM polymerisation" method provides a flexible synthetic approach for combining inorganic scaffolds with amino acids, and the potential to tailor and improve the specificity and performance of hybrid antimicrobial materials

    Short distance properties of cascading gauge theories

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    We study the short distance (large momentum) properties of correlation functions of cascading gauge theories by performing a tree-level computation in their dual gravitational background. We prove that these theories are holographically renormalizable; the correlators have only analytic ultraviolet divergences, which may be removed by appropriate local counterterms. We find that n-point correlation functions of properly normalized operators have the expected scaling in the semi-classical gravity (large N) limit: they scale as N_{eff}^{2-n} with N_{eff} proportional to ln(k/Lambda) where k is a typical momentum. Our analysis thus confirms the interpretation of the cascading gauge theories as renormalizable four-dimensional quantum field theories with an effective number of degrees of freedom which logarithmically increases with the energy.Comment: 47 pages, no figure

    Scaling violations: Connections between elastic and inelastic hadron scattering in a geometrical approach

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    Starting from a short range expansion of the inelastic overlap function, capable of describing quite well the elastic pp and pˉp\bar{p}p scattering data, we obtain extensions to the inelastic channel, through unitarity and an impact parameter approach. Based on geometrical arguments we infer some characteristics of the elementary hadronic process and this allows an excellent description of the inclusive multiplicity distributions in pppp and pˉp\bar{p}p collisions. With this approach we quantitatively correlate the violations of both geometrical and KNO scaling in an analytical way. The physical picture from both channels is that the geometrical evolution of the hadronic constituents is principally reponsible for the energy dependence of the physical quantities rather than the dynamical (elementary) interaction itself.Comment: 16 pages, aps-revtex, 11 figure

    European survey on laboratory preparedness, response and diagnostic capacity for crimean-congo haemorrhagic fever, 2012

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    Crimean-Congo haemorrhagic fever (CCHF) is an infectious viral disease that has (re-)emerged in the last decade in south-eastern Europe, and there is a risk for further geographical expansion to western Europe. Here we report the results of a survey covering 28 countries, conducted in 2012 among the member laboratories of the European Network for Diagnostics of 'Imported' Viral Diseases (ENIVD) to assess laboratory preparedness and response capacities for CCHF. The answers of 31 laboratories of the European region regarding CCHF case definition, training necessity, biosafety, quality assurance and diagnostic tests are presented. In addition, we identifi

    An Upgraded Analysis of ϵ/ϵ\epsilon\prime/\epsilon at the Next-to-Leading Order

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    An upgraded analysis of \ep, xdx_d and \epp/\ep, using the latest determinations of the relevant experimental and theoretical parameters, is presented. Using the recent determination of the top quark mass, mt=(174±17)m_t=(174 \pm 17) GeV, our best estimate is \epp/\ep= 3.1 \pm 2.5 , which lies in the range given by E731. We describe our determination of \epp/\ep and make a comparison with other similar studies. A detailed discussion of the matching of the full theory to the effective Hamiltonian, written in terms of lattice operators, is also given.Comment: LaTeX, 45 pages, 6 postscript figure

    Patients with primary immunodeficiencies are a reservoir of poliovirus and a risk to polio eradication

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    ABSTARCT: Immunodeficiency-associated vaccine-derived polioviruses (iVDPVs) have been isolated from primary immunodeficiency (PID) patients exposed to oral poliovirus vaccine (OPV). Patients may excrete poliovirus strains for months or years; the excreted viruses are frequently highly divergent from the parental OPV and have been shown to be as neurovirulent as wild virus. Thus, these patients represent a potential reservoir for transmission of neurovirulent polioviruses in the post-eradication era. In support of WHO recommendations to better estimate the prevalence of poliovirus excreters among PIDs and characterize genetic evolution of these strains, 635 patients including 570 with primary antibody deficiencies and 65 combined immunodeficiencies were studied from 13 OPV-using countries. Two stool samples were collected over 4 days, tested for enterovirus, and the poliovirus positive samples were sequenced. Thirteen patients (2%) excreted polioviruses, most for less than 2 months following identification of infection. Five (0.8%) were classified as iVDPVs (only in combined immunodeficiencies and mostly poliovirus serotype 2). Non-polio enteroviruses were detected in 30 patients (4.7%). Patients with combined immunodeficiencies had increased risk of delayed poliovirus clearance compared to primary antibody deficiencies. Usually, iVDPV was detected in subjects with combined immunodeficiencies in a short period of time after OPV exposure, most for less than 6 months. Surveillance for poliovirus excretion among PID patients should be reinforced until polio eradication is certified and the use of OPV is stopped. Survival rates among PID patients are improving in lower and middle income countries, and iVDPV excreters are identified more frequently. Antivirals or enhanced immunotherapies presently in development represent the only potential means to manage the treatment of prolonged excreters and the risk they present to the polio endgame. Keywords: Poliovirus eradication, Immunodeficiency-associated vaccine-derived polioviruses, Oral poliovirus vaccine, Humoral immunodeficiency, Combined immunodeficiency, Primary immunodeficienc

    Lesões granulomatosas encontradas em bovinos abatidos para consumo

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    Com o objetivo auxiliar profissionais médico-veterinários no reconhecimento das lesões de bovinos encontradas na linha de inspeção de carnes em matadouros frigoríficos, três condições granulomatosas de bovinos foram pesquisadas e suas semelhanças e diferenças avaliadas. Essas três condições granulomatosas foram actinobacilose (causada por Actinobacillus lignieresii), actinomicose (causada por Actinomyces bovis) e mastite estafilocócica (causada por Staphylococcus aureus). Em 505 lesões encontradas em bovinos abatidos para consumo humano, 40 eram uma dessas três lesões granulomatosas: 24 eram actinobacilose, 10 eram actinomicose e seis eram mastite estafilocócica. De um modo geral, os aspectos macro e microscópicos dessas três lesões eram bastante semelhantes, mas suas localizações ajudavam a presumir sua etiologia. A. lignieresii afetou tecidos moles, principalmente língua e linfonodos da cabeça; A. bovis afetou o tecido ósseo, principalmente o da mandíbula; e S. aureus teve a glândula mamária como o tecido alvo. Histologicamente, os granulomas resultantes da infecção por qualquer um desses três agentes continham uma estrutura amorfa, eosinofílica, com clavas irradiadas, localizada centralmente; essa estrutura era rodeada por neutrófilos íntegros e degenerados, que, por sua vez, eram cercados por um manto de macrófagos epitelioides e ocasionais células gigantes multinucleadas. Esses mantos de macrófagos eram irregularmente infiltrados por linfócitos e plasmócitos que tendiam a se acumular na periferia da lesão, que era cercada por uma cápsula de tecido conjuntivo. Dependendo da aplicação do método de coloração adequado, o agente etiológico podia ser visto em cada um dos três tipos de lesão granulomatosa. No caso da mastite estafilocócica, cocos intralesionais foram observados tanto nas colorações por HE como nas de Gram, nessa última como cocos gram-positivos. O agente da actinobacilose (bacilos gram-negativos) e da actinomicose (bacilos gram-positivos) pôde ser observado somente nas colorações de Gram. Os diagnósticos diferenciais para essas três condições são discutidos
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