5,424 research outputs found
Carbohydrate—protein conjugate vaccines
ABSTRACTVarious pathogenic bacteria have coats of polysaccharide, many with repeating epitopes. Though polysaccharide vaccines have been available for some time, they induce mainly IgM production, and are only moderately protective in adults and ineffective in young children. It was originally shown in 1931 that the immunogenicity of polysaccharides could be enhanced by conjugating to a protein. The last two decades have witnessed the production and clinical testing of polysaccharide—protein conjugates specific for at least four different bacteria which normally cause considerable mortality and morbidity, especially in young children. In some cases, immunizing children from 4 months of age, with a booster early in the second year, has resulted in remarkably high success rates in protecting them from disease. For one pathogen, Haemophilus influenza type b, the success rate has been sufficiently high (>95%) to suggest that this disease might, in time, be globally controlled in this way. The results of immunization with conjugate vaccines to Streptococcus pneumoniae, Neisseria meningiditis and Salmonella typhi are also very encouraging. More conjugate preparations are under development
Maximal superintegrability of Benenti systems
For a class of Hamiltonian systems naturally arising in the modern theory of
separation of variables, we establish their maximal superintegrability by
explicitly constructing the additional integrals of motion.Comment: 5 pages, LaTeX 2e, to appear in J. Phys. A: Math. Ge
Regulation of eosinophilia and allergic airway inflammation by the glycan-binding protein galectin-1
Galectin-1 (Gal-1), a glycan-binding protein with broad antiinflammatory activities, functions as a proresolving mediator in autoimmune and chronic inflammatory disorders. However, its role in allergic airway inflammation has not yet been elucidated. We evaluated the effects of Gal-1 on eosinophil function and its role in a mouse model of allergic asthma. Allergen exposure resulted in airway recruitment of Gal-1-expressing inflammatory cells, including eosinophils, as well as increased Gal-1 in extracellular spaces in the lungs. In vitro, extracellular Gal-1 exerted divergent effects on eosinophils that were N-glycan- And dose-dependent. At concentrations ≤0.25 μM, Gal-1 increased eosinophil adhesion to vascular cell adhesion molecule-1, caused redistribution of integrin CD49d to the periphery and cell clustering, but inhibited ERK(1/2) activation and eotaxin-1-induced migration. Exposure to concentrations ≥1 μM resulted in ERK(1/2)- dependent apoptosis and disruption of the F- Actin cytoskeleton. At lower concentrations, Gal-1 did not alter expression of adhesion molecules (CD49d, CD18, CD11a, CD11b, L-selectin) or of the chemokine receptor CCR3, but decreased CD49d and CCR3 was observed in eosinophils treated with higher concentrations of this lectin. In vivo, allergen-challenged Gal-1-deficient mice exhibited increased recruitment of eosinophils and CD3+ T lymphocytes in the airways as well as elevated peripheral blood and bone marrow eosinophils relative to corresponding WT mice. Further, these mice had an increased propensity to develop airway hyperresponsiveness and displayed significantly elevated levels of TNF-α in lung tissue. This study suggests that Gal-1 can limit eosinophil recruitment to allergic airways and suppresses airway inflammation by inhibiting cell migration and promoting eosinophil apoptosis.Fil: Ge, Xiao Na. University of Minnesota; Estados UnidosFil: Ha, Sung Gil. University of Minnesota; Estados UnidosFil: Greenberg, Yana G.. University of Minnesota; Estados UnidosFil: Rao, Amrita. University of Minnesota; Estados UnidosFil: Bastan, Idil. University of Minnesota; Estados UnidosFil: Blidner, Ada Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Rao, Savita P.. University of Minnesota; Estados UnidosFil: Rabinovich, Gabriel Adrián. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Sriramarao, P.. University of Minnesota; Estados Unido
Detached cataclysmic variables are crossing the orbital period gap
A central hypothesis in the theory of cataclysmic variable (CV) evolution is
the need to explain the observed lack of accreting systems in the ~2-3 h
orbital period range, known as the period gap. The standard model, disrupted
magnetic braking (DMB), reproduces the gap by postulating that CVs transform
into inconspicuous detached white dwarf (WD) plus main sequence (MS) systems,
which no longer resemble CVs. However, observational evidence for this standard
model is currently indirect and thus this scenario has attracted some criticism
throughout the last decades. Here we perform a simple but exceptionally strong
test of the existence of detached CVs (dCVs). If the theory is correct dCVs
should produce a peak in the orbital period distribution of detached close
binaries consisting of a WD and an M4-M6 secondary star. We measured six new
periods which brings the sample of such binaries with known periods below 10 h
to 52 systems. An increase of systems in the ~2-3 h orbital period range is
observed. Comparing this result with binary population models we find that the
observed peak can not be reproduced by PCEBs alone and that the existence of
dCVs is needed to reproduce the observations. Also, the WD mass distribution in
the gap shows evidence of two populations in this period range, i.e. PCEBs and
more massive dCVs, which is not observed at longer periods. We therefore
conclude that CVs are indeed crossing the gap as detached systems, which
provides strong support for the DMB theory.Comment: 12 pages, 6 figures, 2 tables, accepted for publication in MNRA
Preoperative neutrophil-lymphocyte ratio and outcome from coronary artery bypass grafting
Background: An elevated preoperative white blood cell count has been associated with a worse outcome after coronary artery bypass grafting (CABG). Leukocyte subtypes, and particularly the neutrophil-lymphocyte (N/L) ratio, may however, convey superior prognostic information. We hypothesized that the N/L ratio would predict the outcome of patients undergoing surgical revascularization. Methods: Baseline clinical details were obtained prospectively in 1938 patients undergoing CABG. The differential leukocyte was measured before surgery, and patients were followed-up 3.6 years later. The primary end point was all-cause mortality. Results: The preoperative N/L ratio was a powerful univariable predictor of mortality (hazard ratio [HR] 1.13 per unit, P 3.36). Conclusion: An elevated N/L ratio is associated with a poorer survival after CABG. This prognostic utility is independent of other recognized risk factors.Peer reviewedAuthor versio
Non-symplectic symmetries and bi-Hamiltonian structures of the rational Harmonic Oscillator
The existence of bi-Hamiltonian structures for the rational Harmonic
Oscillator (non-central harmonic oscillator with rational ratio of frequencies)
is analyzed by making use of the geometric theory of symmetries. We prove that
these additional structures are a consequence of the existence of dynamical
symmetries of non-symplectic (non-canonical) type. The associated recursion
operators are also obtained.Comment: 10 pages, submitted to J. Phys. A:Math. Ge
A new Comptonization model for low-magnetized accreting neutron stars in low mass X-ray binaries
We developed a new model for the X-ray spectral fitting \xspec package which
takes into account the effects of both thermal and dynamical (i.e. bulk)
Comptonization. The model consists of two components: one is the direct
blackbody-like emission due to seed photons which are not subjected to
effective Compton scattering, while the other one is a convolution of the
Green's function of the energy operator with a blackbody-like seed photon
spectrum. When combined thermal and bulk effects are considered, the analytic
form of the Green's function may be obtained as a solution of the diffusion
Comptonization equation. Using data from the BeppoSAX, INTEGRAL and RXTE
satellites, we test our model on the spectra of a sample of six persistently
low magnetic field bright neutron star Low Mass X-ray Binaries, covering three
different spectral states. Particular attention is given to the transient
powerlaw-like hard X-ray (> 30 keV) tails that we interpret in the framework of
the bulk motion Comptonization process. We show that the values of the best-fit
delta-parameter, which represents the importance of bulk with respect to
thermal Comptonization, can be physically meaningful and can at least
qualitatively describe the physical conditions of the environment in the
innermost part of the system. Moreover, we show that in fitting the thermal
Comptonization spectra to the X-ray spectra of these systems, the best-fit
parameters of our model are in excellent agreement with those of COMPTT, a
broadly used and well established XSPEC model.Comment: 15 pages, 8 figures, accepted for publication in Ap
Avaliação da ementa, adequação do consumo alimentar e desperdício em creches públicas concessionadas no Brasil
Introdução: A garantia de uma alimentação adequada, em seu aspecto quantitativo e qualitativo, éde suma importância para a promoção do crescimento e desenvolvimento das crianças que frequentamcreches.Objectivos: Avaliar qualitativamente as ementas, em termos nutricionais e sensoriais, a adequaçãodo consumo alimentar e o desperdício de alimentos oferecidos às crianças frequentadoras de crechespúblicas de gestão concessionada no município de São Paulo, Brasil.Metodologia: Este estudo é transversal e os dados foram recolhidos nos berçários de quatro creches,que recebiam 200 crianças entre 12 e 36 meses. Cada creche foi avaliada durante três dias, totalizando24 dias e 120 refeições. A qualidade da ementa foi avaliada segundo o método Análise Qualitativadas Preparações de Ementas e o consumo alimentar foi avaliado pelo método de pesagem directa dosalimentos, sendo calculada a adequação segundo recomendações do Programa Nacional de AlimentaçãoEscolar para energia, hidrato de carbono, proteína, gordura, fibra, vitamina A e C, cálcio, ferro esódio. O desperdício de alimentos foi analisado pelo Índice de Resto-Ingestão (IR).Resultados: Os resultados reflectiram que a oferta de hortícolas foi insuficiente em mais de 90%dos dias e, a quantidade de hortícolas folhosas e alimentos ricos em enxofre foi compatível com orecomendado em 62% e 54% dos dias analisados, sendo expressiva a oferta de doces e alimentoscontendo ácidos gordos trans. O consumo de energia, macronutrientes, fibra, vitamina A, cálcio e ferrofoi inferior ao recomendado e o de vitamina C e sódio foi de duas a três vezes superior. O IR varioude 27 a 42% nas creches e de 10 a 49% nos alimentos analisados.Conclusões: Salienta-se a necessidade de revisão das preparações das refeições visando melhorara aceitação pelas crianças, e do planeamento das ementas propostas no que concerne ao aportenutricional e porcionamento per capita estipulados
Desenvolvimento de selo de qualidade alimentar e nutricional para a restauração pública
[Resumo][Abstract
Neuraminidase Activity in \u3cem\u3eDiplococcus pneumoniae\u3c/em\u3e
Kelly, R. T. (Marquette University School of Medicine, Milwaukee, Wis.), D. Greiff, and S. Farmer. Neuraminidase activity in Diplococcus pneumoniae. J. Bacteriol. 91:601–603. 1966.—A method for the quantitation of neuraminidase in the presence of N-acetylneuraminic acid aldolase is described. The neuraminidase content of Diplococcus pneumoniae was found to be dependent on the media employed for growth; the highest enzyme activity per milligram of bacterial protein was obtained with Todd-Hewitt broth. Neuraminidase production was stimulated in D. pneumoniae by the addition of N-acetylneuraminlactose, N-acetylneuraminic acid, or N-acetylmannosamine to the growth medium. Three rough strains of D. pneumoniae, which were nonpathogenic for mice, lacked neuraminidase activity. Seven of 12 smooth strains contained neuraminidase; enzyme activity was not detected in the remaining 5 smooth strains. There was no correlation between the presence of neuraminidase activity and the capsular type or between neuraminidase production and animal virulence
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